dmruschell

I've decided to make my 230hp 283 in my 61 Corvette into a 270hp 283 with a cloned 2x4 setup.

I've also been planning a 327 build for my 1960 Impala and have a 770cfm Holley Ultra Street Avenger (large, I know, but vacuum secondaries should make it ok to use) and mid-60's SBC iron intake (AFB/Holley bolt pattern) that I was going to use for that build. Other components include double hump heads (1.94/1.50 valves) and a Lunati Voodoo cam (http://www.lunatipower.com/Product.aspx?id=2323&gid=287). The car is an automatic with a Turboglide, so I'm not planning on it getting in the upper RPM range very often.

I will have the WCFB intake from my 61 Corvette that I could use to make a more-period-correct intake and carb setup on the Impala if I bought and built a WCFB for it. The question is: how much power would I be giving up by putting a WCFB and 230hp intake on this 327?

I know that the major differences between the 250 and 300 hp 327s of the early 60s were that the 300hp had the double hump heads with 1.94 valves and upgraded from the WCFB to an AFB, so I'm guessing the WCFB will be a bit too small. I figured I'd ask the experts here for a second opinion, though!

427Hotrod

I don't remember enough about the internal dimensions of the iron 283 intakes, but I know the 2x4 WCFB ports are tiny.

The WCFB's on the 2X4 setups flow about 375cfm each. Not sure if single ones were much bigger. I'm sure someone here knows the dimensions.

Probably doesn't help much, but a few years ago we built a 400" with seriously ported/welded 2x4 intake and WCFB's. The difference between that setup and a 750 Holley Street HP on a Weiand Single Plane and another test with a Dart "air gap" dual plane was 45-55 HP difference(500-555 HP range). The carbs weren't really a restriction but the intake was.

That 327 isn't going to need much carb, but the Holley will definitely spank the WCFB. The AFB's couldn't hang with a good Holley back then either.

Why not go "period correct" and install a Z-28 style dual plane and Holley? That's what folks did in the 60's along with a set of MT valve covers.

JIM

dmruschell

Thanks for the info. I'm not looking to get into the 500 hp range, obviously, but 350 hp would be plenty. Torque is what I'm most concerned with though, since it will be moving a big, heavy car. I picked that Lunati cam because it has a good amount of lift, but has relatively short duration (like most of the Lunati Voodoo cams do).

I'm dressing this engine up as if it were a stock 283... kind of. I have script valve covers (though, I'll have the set off of my Vette once I get the finned covers to make it look like a proper 270 hp setup) and am using the old style crankcase ventilation since it is a small journal block. The stock air cleaner for that car is made for a smaller diameter 4gc or WCFB, which is part of why I'm considering using the WCFB.

Basically, I want it to look like a stock 283 while performing like a strong 327. If they made 350 or 383 cranks for small journal blocks, I'd consider going that route to get more torque, but 327 is the best I can do.

Frankie the Fink

Take Holley out of the equation; different design altogether.

As far as WCFB vs AFB; I've run both on my '63.... The dual quad setup you're considering (as 427hotrod notes) will have plenty of CFM for what you want and the WCFBs look better and more original as 2x4s. Correctly setup and with a tweaked timing map my 270hp 283ci will pull right alongside lower HP 327s....in stock trim.

dmruschell

My 61 Vette is definitely getting a 2x4 WCFB setup with the solid lifter Duntov cam.

I'm just wondering if I should stick with my original plan and put the Holley I already have with a matching 327 intake manifold on the Impala, or should I use the smaller WCFB intake from my Corvette and get a carb to match for a more original looking setup. My concern is that I'll lose a lot of power by using the WCFB instead of the Holley, given that I'll have a Lunati Voodoo cam and double hump heads on the 327 I'm building.

Frankie the Fink

Prob above my paygrade...

However, if you add up the 384 cfm air flow of a wide open WCFB and multiply it times 2 that's a lot of mixture pumping down your mill. I don't think your engine will be starved. The sure sign of an amateur engine build for a street driven car is over carbueration.

dmruschell

The Impala wouldn't be getting a dual WCFB setup. If i use a WCFB on the Impala, it will be sitting on the 1x4 manifold that will be coming off of my Vette when I convert the Vette to a 2x4 setup.

I'm just not sure that 384cfm by itself will be enough to feed the 327.

Frankie the Fink

An original 250hp 327ci 1963 motor had the WCFB from the factory. Mine does.

It's OK but not sure I'd use a single WCFB on a hopped-up 327ci configuration... The AFB was used for higher HP setups...

Scott Marzahl

Maybe this will help you. If you use any of the online carb sizing calculators they will recommend a 500cfm carb for a 5,500rpm engine. The L79 327 uses a 585cfm carb
If you want to use a 350 or 383 crank, make sure its a forged piece and have the mains turned down to small journal.

65tripleblack

You are too small with the WCFB if it's only 375 CFM.

Online calculator computes 393 CFM requirement @ 5000RPM for a 327 with .83 VE.

SWCDuke

The ...896 heads used on '63-'64 327/250s had "283 port and valve sizes". In '65 ...461 heads were installed, but torque and power ratings remained the same, so the big port heads with larger inlet valves didn't do anything because the the small port inlet manifold and carb are the primary restriction at high revs. Think NASCAR restrictor plate engine.

The 250 HP engine was rated, SAE gross, at 350 lb-ft @ 2800 compared to 360 @ 3200 for the 300 HP engine, and the 250 may have made marginally more torque in the lower rev range, but it's out of breath by 4500.

My understanding is that Turboglide is basically like Dynaflow - under normal operation it's a one speed torque converter drive and low can only be engaged by manually moving the gear shift lever to L, so you want stump pulling torque right off idle, which is what the OE cam will do better than any aftermarket cam while being easy on the valve train.

If you use a big port manifold with an AFB, you will have essentially a 300 HP configuration, which has more top end power and another 500 usable revs with nearly the same stump-pulling off-idle torque as the 250.

A third alternative is to do a "Special 300 HP" configuration. Search for a thread started by me on this subject. It's easy to find.

I'm more concerned about your cam choice. It has more duration with the same LSA as the OE 250/300 HP cam, so that means more effective overlap, which is going to hurt low end torque. The extra .050" lift is inconsequential, and will likely require higher rate valve springs than OE, which results in higher lifter-lobe interface loads.

My recommendation based on your transmission choice and driving preferences is the OE cam - Sealed Power CS-79 - about fifty bucks at NAPA and the OE equivalent valve springs, VS-677 that cost about 20 bucks a set, or, if you want more top end power and revs without a significant loss of low end torque, the McCagh Special cam if you want to go the extra mile to do the head massaging with a big port manifold/AFB and higher compression to do a Special 300 HP configuration.

As far as converting a 230 to a 270 I agree with the previous recommendation that the WCFBs should be set up as close to OE 270 versions as possible and go from there.

Duke

dmruschell

Thanks for all of that information! I have some questions and comments.

The Turboglide is basically like the Dynaflow, except that the Turboglide doesn't have the low gear that the Dynaflow does. You're stuck in the one gear. It does have a Grade Retard setting that will destroy the transmission if used as a low gear. I haven't really had the opportunity to drive it (the suspension bushings are essentially worthless so it handles very poorly), so I'm not sure how high that transmission will allow it to rev.

Cam choice: Thank you for commenting on this. My thinking was that the higher lift would allow the torque to continue farther throughout the RPM range and not give up as quickly as a stock cam, but I haven't had any real-world experience with experimenting with camshafts. Automatic transmissions generally don't start engaging in Drive until the engine is between 1,000 and 1,500 RPMs, so I wasn't too concerned about it pulling right off idle. There is one cam in that same Voodoo line that is smaller (http://www.lunatipower.com/Product.aspx?id=1981&gid=287). Would that be a good/better choice? Or would you still recommend the OEM cam?

I found your paper "The Tale of Two Camshafts." I'm not sure if that's what you were talking about (I haven't reached the end of the paper yet, but I will), but if it's not, then I will keep searching.

One thing that I tried/would like to try to avoid with my camshaft choice is that on mild engines with an automatic transmission, flooring the car and keeping the transmission in gear as long as it want to will actually make less power than part throttle. At part throttle, the car shifts sooner and keeps the engine in the torque range, whereas keeping the pedal to the floor keeps the engine revved up beyond where it's making usable power. I've experienced this in my 1956 Oldsmobile as well as my father in-law's 1987 Corvette. The Turboglide doesn't have multiple gears, but it does allow the engine to be revved higher and stay there when the pedal is floored.

The heads are 1.94/1.50 heads, so they're good for a 300 (or even 350, I believe) hp setup. But, that needs to be paired with the AFB manifold and a carb to match it. If I go with a WCFB, I might as well be running 1.72 PowerPack heads, as the smaller carb will negate the usefulness of the larger valves (and larger camshaft lift from an aftermarket cam), and the engine will run out of power more quickly. Please correct me if my understanding is incorrect.

From what I've read, the Voodoo cams don't require a stronger valvespring, since the closing side of the lobe isn't as aggressive as the opening side. I'll do more research on this.

Thanks again!

dmruschell

Well I figured out my solution.

I checked the manifold that I bought, and it's an early 60s AFB bolt pattern, so my Holley won't fit. (I didn't realize there was a difference since the modern version of the Carter - Edelbrock - uses a Holley bolt pattern.) Fortunately, I'm pretty sure Edelbrock carbs still have the holes for that older AFB bolt pattern so I can reuse the one that's on there for the time being. Eventually, I'm going to get an original early 60s AFB carb (or just the air horn), which has the smaller air cleaner diameter and will let me use the original air cleaner. It's the best of both worlds: original air cleaner and enough CFM to support the power I'll be making.

SWCDuke

Thanks for refreshing my memory on Turboglide. I remember a high school friend's parents had a '59 Impala with TG, and I now recall the Gr setting on the gear selector.

The problem with most aftermarket camshafts is that they have more overlap than the base engine OE cam. Overlap kills low end torque, which means less low end power. Some may make more top end power, all other things equal, but with your application, power from off-idle (or maybe I should say converter stall speed) to about 3000 is more important than power above that range.

The "Tale of Two Camshafts" article is the one I suggested you read.

I don't like the second cam compared to OE, either. It still has too much overlap IMO. Higher lift is more important for top end power, but doesn't have much effect on low end torque/power when flow velocity is relatively low. The low overlap OE cam should idle butter smooth in Drive at no more than 500 and pull very strongly from a stop. A higher overlap cam will require a higher, but likely less smooth idle speed and more "creep" in Drive, but won't be as responsive from a dead stop, and will have poorer fuel economy.

"If I go with a WCFB, I might as well be running 1.72 PowerPack heads, as the smaller carb will negate the usefulness of the larger valves (and larger camshaft lift from an aftermarket cam), and the engine will run out of power more quickly. Please correct me if my understanding is incorrect."

Correct. The small port manifold and lower flow carb essentially act as a restrictor plate, and are the limiting flow factor, so the big port heads won't make significantly more top end power, but the small port heads might make a little more low end torque/power.

The small port manifold and WCFB will make useable power to about 4000-4500. The big port manifold will make about 10 percent more peak power with a useable range to about 5000. The Special 300 HP config with the McCagh Special cam will add another ten percent with a usable range up to at least 6000. All three will make about the same torque/power from off idle (or converter stall speed) to about 3000.

So your tradeoff is primarily between top end power, original appearance, and cost.

This story might aid your decision process. A few years ago at a NCRS chapter meet in Palm Springs a member asked me to drive and evaluate his car - '69 coupe, base engine, TH 400, 3.08 axle. In normal driving, part throttle up to about 3000 it ran very well - torquey and responsive. Then I locked it in first and at WOT the power seemed to peak at no more than 4000, and it was wheezing before 4500. That wasn't right.

Further investigation by the owner determined that the heads were from a 350 truck engine and had "283" style small ports and valves. Everything else was OE including the inlet manifold and Q-jet. That was a new one on me because I never realized that any 350s were built with what were essentially 283 style heads.

The owner found a set of correct big port heads, massaged them as outlined in the Tale of Two Camshafts article, and installed them on the engine. He elected to not go into the block and replace the OE cam with the McCagh Special.

At a subsequent meet he asked he to drive the car again. I started by doing a launch - brake on - floor the throttle which instantly brought revs to the converter stall speed of about 1800, and release the brake. It lit up the tires. So I stopped, released the brake, and punched the throttle. It just hazed the tires and took off very strongly. I was locked in first gear and watched the tach. It just kept climbing, and I finally released the throttle and shifted to second at 5500, but it wanted to go higher. Peak power felt like 5000 with virtually no rolloff to 5500. The torque curve is very flat, which makes the power curve very linear - about as good as it gets for a strong and responsive road engine.

The difference between the two configurations was literally like night and day.

BTW it had A/C, and that engine with the TH 400 and 3.08 axle was very nice - very smooth, torquey, and responsive in normal around town driving with enough bottom end to light the tires from a dead stop and a tall enough axle to make freeway cruising comfortable without the engine screaming. It would be comfortable cruising around town or a long interstate trip, and would probably top out at close to 140 MPH. It was the strongest base 350 I've ever experienced.

The problem in this case was the small port/valve heads. They acted like a restrictor plate. The big port manifold and 750 CFM Q-jet were of no value because the small head ports/inlet valve began to choke flow at 3500 and got worse from there on up.

The ideal road engine should have a very flat torque curve, and since HP equals torque (lb-ft) times RPM divided by 5252, a flat torque curve will cause power to increase linearly with revs. This is the case with the McCagh engine. Of course torque curves do roll off at higher revs, but the slower the rolloff the flatter the power curve up to the rev limit. The overall result is an engine that is strong and responsive from off-idle to the rev limit.

Duke

dmruschell

SWCDuke,

I think I have those same heads from the truck as the ones you mentioned on my Impala right now. The valves are the same size as the 283 heads and are low compression.

I'm hesitant to mess with the heads, even though I am intrigued by the McCagh cam. I wonder how that cam would do with aftermarket heads with modern airflow designs.

With the knowledge that the Holley I planned to use won't fit on the intake I bought, and that I can run an early 60s Carter AFB with the original 1960 Impala air cleaner, I will go ahead and do that. I'll probably run 1963-65 Corvette hard fuel lines as well. While not correct for a 1960 Impala, it will be relatively period correct and not look out of place. The Edelbrock that's on there now will serve me fine, even after the engine is rebuilt with the AFB intake (Edelbrocks have dual bolt patterns), until I can get the Carter I'm looking for. So, the original question is answered, but I'm enjoying picking your brain about this stuff.

About the camshaft selection (because this subject fascinates me), I kept thinking of the valve overlap between the stock cam and the Voodoo cams I mentioned. While the duration at .050 on the Voodoo cams I mentioned is 15-20 degrees higher than the stock cam, the advertised duration is significantly lower. Using the specs for the Comp Cams Factory Muscle 300hp cam, the advertised duration for the stock cam is 319/320 (intake/exhaust). On the larger of the two Voodoo cams I mentioned, the advertised duration is 256/262. It would seem that, at less than .050 valve opening, that the Voodoo cam would have less overlap. Most have said that the smaller Voodoo cams don't really lope at idle, either.

In my 350 on my 79 Vette (high compression pistons, aluminum heads, Edelbrock RPM intake, etc), I used to have the Edelbrock Performer RPM cam (http://www.edelbrock.com/automotive/...7102&submit=go). When the piston rings wore prematurely and it needed to be torn down, I had that cam replaced with this Lunati Voodoo cam: http://www.lunatipower.com/Product.aspx?id=2325&gid=287

Advertised duration went from 308/318 to 268/272
Duration at .050 went from 234/244 to 227/233
Lift went from .488/.510 to .489.504.

The Voodoo lopes a bit less than the RPM, but the biggest difference is the wide power band. Neither cam does much below 1300, but power at 2,000 RPM is significantly more with the Voodoo than with the RPM. The RPM cam really didn't come alive until 3500RPMs, but the Voodoo starts making power around 2500RPMs. Both have pulled strong as high as I've revved them.

I realize that the duration at .050 is less on the Voodoo cam, which goes with what you've been saying. But, I also want to say that the bigger difference in advertised duration probably plays a role as well. The lift difference between the cams is basically a wash.

Even with the shorter duration, the about equal lift between the two cams means that the high RPM power is still there with the Voodoo. That's what I'm looking for with this engine (and appears to be your goal with your cams, though you took a different approach to get there): Power that starts at a relatively low RPM range and doesn't give up throughout the RPM range that I'll be using. It seems as though the work on the heads allowed you to use factory lobes with tweaked valve opening and closing events. With the Voodoo, modern asymetrical lobes, and fast opening ramps (approaching solid flat tappet or hydraulic roller ramp rates) were used to keep the low duration for low end torque while keeping relatively high lift for high RPM use.

Again, thanks for all of the information.

SWCDuke

The Special 300 HP configuration with the McCagh Special cam is very tightly system engineered for a specific set of requirements including an E/I head port flow ratio very close to 0.8 and relatively high compression. As I said in the article it will not work well without the required head massaging, and the CR range should be 10-10.5:1.

The LSA and effective overlap are the same at the OE base engine cam, so idle behavior including manifold vacuum is the same.

It's the improved head flow and late phased inlet event that combine to makes the top end power while still maintaining stump pulling low end torque.

There are literally hundreds of aftermarket cams, some with fancy names like Voodoo, which is just marketing BS. Most provide timing that is typical of OE SHP and aftermarket cams of the sixties, but with more aggressive dynamics. The McCagh Special is nearly identical to the LS2/3 duration and phasing on the inlet side, but has shorter duration on the exhaust side due to the high E/I ratio of massaged vintage heads compared to stock vintage heads or LS heads. And since the McCagh Special uses OE lobes it only needs OE valve springs, which maintains the bulletproof OE valve train reliability.

When you get into more aggressive lobe dynamics, which need higher rate springs, you dramatically increase the chance of cam/lifter wear problems.

The story is summarized by the very flat torque and power curves, which is what you need with only a one or two speed torque converter transmission. The configuration also works very well with a wide ratio manual, so a base 283, 327, or 350 engine can be configured to behave like a base engine at idle and low revs while making SHP top end power and revs all the while appearing to be a totally stock base engine.

Back in the day we called them "sleepers".

Duke