It has been awhile. You must be real busy in "real life" cause I haven't seen you on the forum much lately, although if I had as many projects going on as it sounds like you do, I wouldn't be on the forum much either.

When I decided to turbocharge my SBC 427, there was some question as to whether I would be able to use my 6.125" rods(although I had a line on a brand new set of carillo titanium rods and wrist pins that were 6.100" long - they're still available if anyone wants them, $1600 brand new, plus $800 for the wrist pins) and still lower the Cr from 11.27 to 8.5 (my target CR). We were concerned that the 1.175" compression height would be too small and force the rings to be too close to the piston top, but JE managed to fit them all in and use a dish large enough to drop the CR down to 8.5. We even ended up witht he top ring .310" dwon, which is right where it needs to be. Of course I had to give up a bit of quench area for the dish, but there always seems to be a compromise.

Thanks for the compliment. I'm interested to hear about/see the 377 TT you're building/planning.


[Modified by Monty, 11:37 AM 5/7/2002]

 

Wow.

Members, Monty here is the person to see for all your small block stroker questions. I am very impressed with what you've been able to accomplish. I wouldn't have thought it was possible to lower compression enough in a 427 SBC to turbocharge.
Expensive...but NICE!!!

The 377 is not started yet. It is just planned.
I am busy with my 427 BBC conversion project right now. That's in the Shark.
In my 68 Firebird, I am busy getting the rusty cancerous panels off and getting it ready for a paint job, which I'm going to have to do myself.

I am on the forum, but much more in the background, kind of overseeing things more than commenting on posts. I'm more into the observer mode because of how busy I am.

Are you bringing your "Tiger Shark" to the Cruise In by any chance???

 

I was hoping to make the Cruise-in, but the guy who helped me with my headers, intercooler, and exhaust took 4 months to complete it, rather than the "3 to 4 weeks" he promised back in January :rolleyes: . I'll probably be dyno testing/tuning that weekend. Next year I guess....


[Modified by Monty, 2:25 PM 5/7/2002]

 

Thanks for all the help guys. I'm really excited about this engine build. Let the Graduation money come!!!

I'm going to try to get out to the track Friday. It just depends if I get back from fishing in time.

I've been running 12.6 with 235/60/15 Eagle tires, stock clutch fan, and 3.36 gears. I just went to 4.11s, elactric fans, and BFG drag radials. I'm really hoing for LOW 12s. What do you guys think?
Jay

 

This made for some interesting reading. I have a 406, that with the help of some forum members (Lars, Ruff71, mountainmotor, etc) is finally seeing the light of street use.

Let me ask you guys about timing for a second. I had SERIOUS detonation issues with my 406 when I bought it. ironing those issues out, I learned that timing these larger small blocks is not quite the same as the 350 or 327. That 36-38* is just too much, and that 32-34* is about perfect. Any input on that?

One of the mistakes made by whoever built my engine originally was putting ported and polished "041" 64cc heads on a 406 that had been zero decked with flat-top 2-releif pistons. That pushed comp ratio above 11:1, and there was no way I could run this on the street.

Now, the cam will be changed this summer. Currently it's a solid lifter, dual pattern long duration of unknown origin. From my measurements it's very similar but a hair more radical than the 1970 LT-1 cam. I have this car dialed in as best as I can currently, and it's still barely streetable. Cam gives me 8-10 inches Hg vacuum at idle, which is just barely enough to operate the lights and wiper door, because those systems are in 100% perfect working order. It is NOT enough to properly operate the power brakes. I had to buy a separate vacuum reservior, and even so, stopping when backing out of the driveway requires 2 feet.

The car currently has 3.73 rear end, with a TH-400. I'm also assuming it has a higher than normal torque converter, since I have some slippage, plus the cam would require it. This makes highway driving rather unpleasant to say the least. I'm spinning 3500 rpm just to keep up with traffic. Gets old after an hour or so.

Anyway, just keep in mind what type of driving you are going to do with your car. If you're ONLY taking this car to the track, have a good supply of 93+ gas (boosters don't do dick), then by all means go ***** out. BUT....if you ever want to drive you car when you go out to eat, take trips in it, go to Carlisle, etc. i would seriously consider your engine package as a whole. This means a decent midrange cam, comp ratio under 9:1, mid-rangey rear end gears, etc. I'd rather have a 12-13 second car I could drive and enjoy than a 10 second car I could only do 1/4 mile runs in. Just depends on what you're after.

 

seem to me a waste of time and money to use a stock chevy 400 block to build a engine of this size and power. buy a HD block. :chevy

 

Thanks Monty & Momo for the excellent information!

Basically I'm going to stick with an NA setup for now, but may consider a centrifugal supercharger later on...

Just looking around and playing with numbers, theoretically if I can find 0.930 CH pistons (lowest stock ones I've seen is 1.000 CH), I could run a 6.385 rod.
That'd put the r/s ratio up to 1.600 and still have a good compression range for pump gas.

As for ring seal (which might be a problem with a piston like that), I should be pretty good since I have hopefully landed a good deal on a 5-stage pump which should generate some serious vacuum in the crankcase! :D

Tony


[Modified by HunterRose, 2:17 PM 5/7/2002]

 

3.73-4.11 gears were the norm in the sixties. Most sportscars had them. That doesn't mean they didn't drive them, it just means they used more gas than everybody else.

I like having a motor that is on the verge of streetable. I drive my car all around (It's sitting in the school parking lot right now). It sure is nice to know that you can smoke just about anybody you'll see on the road.

I simply can't afford an aftermarket block, fuel injection, overdrive, and the like. But that doesn't mean I can't have a fast car. I just have to live with a less streetable car.

I wish I had the money to do an awesome build-up. But I don't. So I have to do it myself, and get suggestions from people that know what they're doing so I can get it right the first time.
Thanks,
Jay

 

Well, a 12.6 on a 350 engine is very good performance. But if that's not quick enough, you may want to simply consider a 406 with 6-inch long rods. That'll give you the power to hit low-12's, possibly 11's, especially with the rear end you're running. Plus the 406 will be a very good street engine that won't need a huge cam to run those times. I doubt if you'd ever have to exceed 6500 rpm, so you could save yourself the trouble and go with a hydraulic roller cam. You won't even need to use a forged crank. You could go with a cast steel crank, or even an iron crank and be just fine. Go ahead and get good forged rods though, but I-beams would be sufficient.

Why a 406 instead of a 427 SB? Because it could be the difference between a $4000 build up and a $10,000 build up, and that's conservative. The 427 will make tons more power, sure. But if you want to play that hard, you gotta pay.

If you decide to spray nitrous on a 406, you'll definitely be buried very deep in the 11's. Plus you'll have an engine you can live with easily on the street. A 406 built right is a good motor. Might be something to think about.

3.73 and 4.11's were certainly available in the 60's, but they were not the norm. Transmissions of the day only had a 1:1 top gear, so rear ends tended to be 3.36 or numerically lower. In 1968, a 3.36 posi was the best rear end you could order. (Correct me if I'm wrong, but my research indicated that). You could get an aftermarket gear set, and racers did. But from the factory, I think 3.36 was the best you could do.

An option that a lot of people like to use is to keep their 3.08 or 3.36 gears the same, and get the extra low end gear using a Richmond 5 or 6 speed. That makes gears 1-4 the same as a Muncie with a performance rear end, but you still get the tall 1:1 or OD for the cruise.

 

The rotating kits that I have been pricing for a 406 would still run me $1200. The 427 is only $1800. Where sdoes all of the extra cost come in. I've never took on a project like this, so I may be forgetting about something. Even if I can't afford the best heads, My Dart Pro 1's should be decent.

I'm really hoping to hit 11's in my 355 before I put in the 427. I think I could hit 10s all motor eventually.

Thanks for all the help,
Jay

 

not streetable (based on my not streetable 406) means that:

1. Idle is rough at best. put car in neutral at stop signs, lights, then BANG! :eek: back in gear. this gets old quick. of course, you can set the idle speed higher, but then you are banging into gears even harder when shifting, and you are also dieseling the car when you shut the engine off.

2. You have no lights or power brakes

3. You must buy race gas. which, when you can find it, is only allowed to be dispensed into 5 gallon containers, and not directly into the vehicle.

4. Say you actually fill up your gas tank, at 8 mpg with a 14 gallon tank, you can drive only about 50 miles from home before you have to turn around. unless you want to carry fuel containers in the storage compartment.

5. You have very poor cold starting

The whole advantage with using a 400+ CID small block is the displacement. Don't use similar 302/327/350 logic. Use big block logic. Get that torque curve starting low and going broad. Use what you have now (heads, gears, tranny converter) and contact somebody like Elgin or Schneider cams, and have them give you the #'s optimal for what you have.

When my 406 was 11.5:1, ported polished heads, single plane manifold, blah blah and all that crap, it was so horribly tuned down for street use that it was a DOG! No smoking tires, no pinned to the seat feeling. and I was getting 7 mpg :eek: I lowered compression to 9.7 by using stock 400 SBC heads, put on a Q-Jet, got my timing set up correctly, Edelbrock performer intake, and now it's one hell of a fun ride, at 14 mpg too!!! Now I have to be careful on dry roads. And this is with the current cam, which is not optimal, and the 2" dual exhaust. This summer I'm increasing exhaust to 2.5", installing a cam selected for me, and then I should have too much torque, thus I can go for a milder rear end gear.

I'm still learning, but trying not to repeat mistakes made by the previous owner of my car. keep in mind that old adage: "horsepower wins arguments, torque wins races" :chevy

 

Teen with 74, there is a lot of hidden cost. A good set of small block aluminum heads will pretty easily run you $1400. If you want to have any additional machine work to improve them further, add $500, or less-depending on what you do. Machine work on your block, should include align-honing the mains and honing the bores with a torque plate. Then you want it filled on the bottom, and machined for clearances. I think machining the block will cost you around $1500 give or take a few hundred. The intake manifold will cost a few hundred. The carb, if purchased new will cost $400 to $700, depending on what you get. The solid roller cam you propose to get is about an $1100 set up, including cam, roller lifters, roller rockers, and chrome-moly pushrods. Headers to flow what this beast will want to flow will run you $400 or so for a set of Hooker Supercomps. The rest of the exhaust, once optimized, could run you another grand, because no one makes a good enough aftermarket bolt-on exhaust system for a C3 Corvette. You'll need an electric fuel pump for a few hundred, and an upgraded radiator for around $500. New water pump for a hundred. A baffled oil pan with increased capacity is probably 2 or 3 hundred. You definitely need to upgrade all your U-joints at the very least, and will almost definitely need to upgrade your transmission yoke and driveshaft. About $600 for all that. And we haven't even gotten to improved tire traction.

So you see how it can add up? That $1200 kit has just become about $8,400 for everything I've just estimated. And that's IF you do all the work yourself. Additional labor for building up your engine should cost a few more thou.

It is just like the old adage, if you wanna play, you gotta pay.
Don't let that stop you. But don't be in too big of a hurry. And whatever you do, try not to add up how much you have left to spend. It can be disheartenning.

Other than that, if a 427 is what you want, then go for it.
But do read the post just before mine about living with a hipo engine. All those things can be true in your case. Your driver 350 Vette could easily be restricted to almost racing only with an upgrade to a super small block.
But a mildly built-up 406 on the other hand will give you the best of both worlds...without spending a buttload of cash on trick parts and machine work.

 

I have the good heads alredy, Dart Pro 1s. I talked my machinist the other day, the block work won't be too bad. I already have headers (though I'm looking at getting better ones) and a nice exhaust. I also have the intake, carb, electric pump, and so on. The oil pan I need is $200. I already talked to a cam ginder about a custom cam kit. I think I'll be ok on that.

I appreciate all of the help so far. I haven't made up my mind at all, I'm still weighing my options. I've also talked with someone that is iterested in my short-block, so that will give me some extra money. I'm just gona see how evrything goes. I'm not in hurry at all, I just get excited. Hehe
Thankn,
Jay

 

Monty awsome engine work!!! Best iv seen ever!

Could post pictures of those Carillo Ti rods you have?

Thanks ,Joni

 

MoMO,sound advise and insight when approaching a project like this.
Phil

 

Joni,

I don't have an pics of them, but I could get some to you tomorrow if you're really interested - they're at the machine shop.

 

Monty, what you said here is very interesting to me, because I've been trying to decide where to put my money. Heads or roller cam? Basically, I can get "as cast" Dart heads and a solid roller cam, or Dart CNC ported heads and a solid flat tappet cam. Cost is the same. What do you think? As an added bonus, I can swap a few flat tappet cams in there for much less investment than roller cams.

 

Do you have the flow numbers for the cylinder ehads you are consdiering. Dart is usually very good about posting their flow numbers for their heads on their website. I had my Dart heads flow tested and they were practically identical to what Dart claimed, a little better flow at some points, so I feel comfortable with their accuracy.

One thing to consider about Dart "as cast" heads is that they are just that. They are intended to be ported by hte engine builder ebcuase they are typically intended for racing applications. For instance if you compare a AFR head vs a Dart head out of the box, you'll probably see that the AFR out flows it, but compare one of Dart's CNC ported heads or a pair of Dart heads that were professionally ported and it's a different story.

I'd go with the good heads first, and then upgrade to a roller cam later on if you want to. There's still plenty of power to be made with tappet cams, especially solids.

 

The point you mentioned about the "as cast" Darts makes sense to me, and it explains alot of what I've read. Like you said, the Dart CNC heads flow great! The as-cast models aren't as impressive. Here are the numbers:

Dart 325cc as-cast:

Intake at 28"
.2 147
.3 223
.4 281
.5 326
.6 353
.7 371

Exhaust at 28"
.2 136
.3 175
.4 210
.5 233
.6 249
.7 258

Dart 335cc CNC (CNC ported version of the 325)

Intake at 28"
.2 174
.3 245
.4 306
.5 353
.6 383
.7 401

Exhaust at 28"
.2 136
.3 178
.4 235
.5 265
.6 282
.7 296

 

Flareside, I agree here.
I'd go with the heads and the solid flat tappet cam, because you'll see a good power per dollar investment. Then later on, you can always upgrade to a solid roller, but that won't be as good a power per dollar investment. It provides a good increase but the money is substantial for that conversion. And the solid flat tappet cam won't be that far off of a roller cam.