Other important things like stall speed and weight also make HUGE difference at the track.. If you have cam that makes power from 4000 - 7000 RPM and you a running a 2400 converter, you are loosing big time etc...
Weight gives you approx. .1 for each 100 lbs saved and more for rotating mass.. Wheels and tires alone can make a huge difference at the track..

 

"At the track"
"On the Street"

...ya gotta decide which one you want. (We already know what Dep & GSC3 are looking for...)

Good streetability is achieved through small intake runners, dual plane manifolds, and the proper cam. Not gonna be a big winner on the dyno, but very good for getting on freeways, pulling away from stoplights, etc.

For the track, large intake runners, single plane manifold, and rumpity big cam is a winning combo.

Mix & match means the best of neither

 

there are always those who want lots of power for very little $, they expect to go to a builder/mechanic and so they can get free advice with no intention of having the builder/mechanic do the job. Why ppl expect free advice is beyond me, do they work for free? I don't give advice to others on build-ups other than to agree to whatever they say and wish 'em luck. It has been stated on this and other forums many a time that a proper build up costs, very few have the ability to build a killer engine on the cheap, but then again CHP is cheap and so is advice and as long as I am not paying for the build up 2 or 3 times because of non matching components I really don't care.
there you go Dep how was that one!

 

It is a myth that single plane intakes are mostly for the track. I ran a Victor jr. on a 250 HP 327 and it performed just fine.. Plenty of bottom end torque.. I'd take a single plane over a dual plane any day...street or track..

 

most guys don't do their homework.
when i see an exceptionally good combo, i write it down in my notebook. 8 so far in 4 years.
.
Bubba's don't buy vizard's books, they don't even know who he is or what a book is.

 

This may be true. I had a single plane on my old 289 Mustang. Worked well. But we're just trying to put forth some conventional wisdom here -- basic rules of thumb that are a starting point for the novice. Let 'em mess with different manifold types as they progress in their knowledge.

BTW: A lot of time & money is wasted on intake swaps on otherwise stock engines. Not the place to start at all...

 

Being stuck in Calif means limitations for Vettes 1976 newer....so,my rebuild plan must cover smog but my emphasis is suspension/gearing for the twisties.My stock L-82/3.70 4 speed works well in that envoirnment..autocross days over..need to decide what to do with engine when time comes...got exhaust worked out...

 

Ahhh..now we have some dissent

Some more suggestions from me. Note that I only run stick shift so those with autos need to be more conservative.

Carb...a double pumper carb will go far towards curing bog, even on an automatic. But it will drink gas like there's no tomorrow. I have NEVER heard someone say they installed a double pumper and now get better mileage.

Lars tune...no doubt about it. HE's the master. But sometimes it's a long wait before he's in your area. Read and observe his FAQs until he gets in your neighborhood. When he gets in your area, WATCH AND LISTEN to everything he says and does. He works fast, but if you can see him work his magic on a few cars, you can pick up a lot. I am still kicking myself for not bringing a VCR instead of a still camera

Custom ground cam...bobs77vette is teasin' me because of my other thread. But there is nothing wrong with getting a custom ground cam for your car if it's not too expensive. It can be set up to your style of driving and you won't have to acquire a collection of bar-b-q pokers to get the right grind

At the track/on the street...here is where I veer from a lot of you guys. I see absolutely NO POINT in building up a motor JUST for the street. Tuning it up from Lars is great. But building in tons of horsepower/RPM/tork/performance to drive the speed limit just doesn't make any sense to me. And I KNOW you guys don't exceed the speed limits on public thoroughfares
HOWEVER, I don't think that a street/strip dual purpose car is impossible. It all depends on how much wrench-turning you are willing to put up with. Gordonm has a VERY nice combo that I would highly recommend. But it does involve a solid lifter cam, which will require more maintenance than a hydraulic cam. Another good street/strip setup would be the 350/350 hydraulic cam version from 1969.
If it were me I'd have at least the 10-1 compression and pour in some lead supreme or other octane booster that we know WORKS.
Remember the HOT engines from the 60s were driven as dual purpose cars. It can be done.

A rear gear for the street...rihwoods mentioned he has a 3.70 rear gear. Good choice! I think I would call a good street rear gear anything from 3.35-3.83 with 3.83 being somewhat marginal. I have a 3.73 in my '04 Silverado and with the 4-speed auto I get acceptable RPM and good mileage (18 around town). Yet I can fry the hides at will.
Of course, this is with a computer/fuel injection engine and 4-speed auto (325 V8).
I would put gears of 3.91 and higher in the "strip only" realm. I drove a car on the steeet with a 4.10 gear back in the 70s and 4th gear was like 2nd gear. The acceleration was awesome and you were smashed into the seat. But at highway speeds the engine was really whining.

gdh said "very few have the ability to build a killer engine on the cheap".
I agree. But we aren't talking KILLER engines here. We are talking engines that run at reasonable expectations for what they are.
One of the great things about the smallblock Chevy is the huge gains that can be achieved at relatively little cost. That's one of it's GREATEST features. You shouldn't have to spend the price of a hemi crate motor ($10,000) to get great results from a smallblock.

Now this thread wouldn't be complete without me mentioning the 302 Z-28 motor Consider...302 cubic inches and they were able to get 350+ horsepower out of this engine. Some estimate it to be even higher than that. Was it streetable? Yep!!...people bought and drove them on the street. Was it fun to drive? Considering this car could blow the doors off many big blocks, I'd have to say yes
Is it PRACTICAL for the street...probably not for most people. Unless you plan on visiting the local drag strip or road race track every weekend. But the fact that that kind of power can be obtained from a tiny 302, means there is an amazing amount of potential in the smallblock. That's why I find it so hard to believe that folks are having such a tough time achieveing it.

I've gotten a lot of e-mails and questions online about how my 302 build is doing. Unfortunately, the answer is not well. The big holdup is the crankshaft. Everything else is still available and fairly reasonable to buy.The crankshaft, however, is VERY pricey. Crower is the only one I've found that has it and it's around $2000. You can understand that I am reluctant to drop that kind of money JUST on a crankshaft. A custom-ground crank is in the same price range. So I am screwed either way. I have some alternatives to the 302 in mind, including a 377 cubic inch Cheetah engine. Since the engine build is a ways down the line, I am not under the gun on deciding what to do. Anyway, enough of that

Page62 said "BTW: A lot of time & money is wasted on intake swaps on otherwise stock engines. Not the place to start at all..."

Quite true. Back in the 60s when cars came with high compression and
a decent cam and dual exhaust systems, the carb/manifold was usually the first thing to be yanked. Followed by cam and headers. Ford even had a "Muscle Parts" catalog that listed the different "Stages" in hopping up an engine. Stage 1 was always a manifold/carb.
With Vettes of the post-'70 era, this is probably NOT a good progression. Bolting a big/different carb on a mid-to-late 70s Vette will probably not get much performance gain and may actually HURT performance in some instances. Better off spending the money on a plane ticket for Lars to work on what you already have

Dep

 

My opinion, two areas of confusion to the small block owners when doing modifications:

1.) Most of the modifications raise the RPM power band and bring you higher horsepower only at higher RPM levels, sometimes at the sacrifice of low RPM torque and HP. This can be remidied by higher compression. The answer is clear, push compression as high as you can to accept the premium gas in your area. Push it to the very edge! People look at compression and say "another point will only increase max HP by 1% so I will stay safe and just keep it a point lower" without having any idea of just how much it helps in lower RPM torque and drivability. What a mistake. Maximizing compression involves very carfeful head, cam, and piston measurements.
2.) People are confused about net vs. gross horsepower. If you engine builder or the crate engine specs says you have a 400 horsepower engine, you will probably get less than 300 when you dyno it. Transmission eats alot, accessories eat alot. And expect about 10% loss just due to tuning issues with the carb or distributor. Depending on who the engine builder is, another 10% will be lost just because of the way the engine was built (i.e. - the 400HP figure well be applicable only for the blueprinted, perfectly balanced and speced, perfectly built engine).
3.) From what I've read, I trust dyno's less than drag strip HP measurements. I get this from reading about 20% differences between stock cars measured on different dyno machines. A dyno is not the end all of measurements unfortunetly (but it's good for tuning). A drag strip 1/4 time, corrected for temp and elevation, is more accurate in my opinion.
4.) Last note - actually I saw only 2 post recently on the "why doesn't my engine put out more power" nature. One keeps on reappearing because it's on it's 4th page or so. I think most of us are happy with our smallblocks.

 

MY GOD!!! We agree on something! Quick, somebody call me a doctor...I feel faint.

Consider this, Dep. The L82 motor is the same engine as the 350/350, except for the heads, exhaust, and smog junk. Same cam and short block. Install true duals, do a head swap with higher compression...and voila! Instant 350/350.

So I guess I have a street/strip combo engine after all. The el cheapo heads I purchased have the same specs as the 350/350 heads, with the added bonus of vortec-style chambers (and better flowing runners). Only difference is my CR is a little lower in order to use pump gas. (Check my sig.)

So now we agree TWICE!!!

 

It`s clear that most of the members that replied to this post know what their doing. Huge lists of performance purchases proudly displayed from wealthy aftermarket sites with high advertised and promoted parts do not automatically mean performance.

 

page: STOP IT!!! YOU'RE FREAKIN' ME OUT!!!!


One thing you have to remember...your car is much heavier than the 1969 Vette with the 350/350. So duplicating the specs of the '69 engine will not necessarily give you the same performance of that car.
The engine is cool . You have an excellent base to work with. You just may have to run a somewhat steeper gear to offset moving the heavier car.

SpyderD: Do a search and you will find numerous posts complaining about
lack of power or satisfaction with the engine mods in guy's cars. Otherwise, I agree with you 100%!!

Ironcross: Well said and my point exactly!!!

Dep

 

Dep, you're losing your touch. Too much agreement here. While this thread is informative, it's not as entertaining as other Dep threads.

 

Yeah...I'm turning into the "kindler, gentler" George Bush Sr. version of me. I need to let fly with some outrageous stuff. Just can't think of any right now

Dep

 

heads from the 60's?

 

Heads from the 60s. As in 1969-70 Z-28 heads. Bigger valves and smaller combustion chambers than any of the mid-to-late 1970s heads.
Angle plug or straight plug, they both worked great. I guess it's time to bring back the Old Reliable website

http://www.z28camaro.com/oldrel.html

Horsepower 456 @7700rpm
Cylinder heads #3917291, completely stock, no porting allowed!
Stock rocker arms & valve springs
Intake 302 aluminum intake, casting #3917610
Carburetor Holley, #4053, 780 CFM 4bbl

Dep

 

In comparison to heads from the 70's...hell yes! The 60's heads had smaller combustion chambers and smaller runners, both of which make better power, but more smog. Heads from the 70's were the byproduct of government mandates -- in other words, junk.

Take a head with 60's specs (67/64cc chambers, 165cc runners) and 90's technology (vortec-shaped chambers), and you've got a winner!

Even Dart recommends its Summit-brand heads over some of the bigger runner volume heads in street-strip applications

 

Dep,
You could side with the fellow who several days ago suggested we should give up on these old cars and buy C6s. Easy performance upgrade! That might evoke a spirited response.

 

Well it got my attention. I guess we should all run out and buy a new piece and be like the rest of the new Vette owners. 65-70 G`s for a Z06 that will immediately be reduced 15-20 grand when you drive it out the door. No, I dont think so.

 

You are making my point quite nicely. Only an idiot would think an actual head made in the 60's is competitive today.