new super street engine
 

Seeing how there isn't a lot of traffic on this site in this category anymore I figured I would ask a question get some opinions. I'm thinking about building a new engine for my 70 Chevelle super street car. Right now it has a 505 inch stock block big block Chevy that made about 860 horsepower on the dyno. So it's middle-of-the-pack horsepower wise. On a decent day it'll run 138 miles an hour or so on the stop. Because I would rather not fabricate new headers and change the combination a bunch by adding a ton of horsepower I was thinking a better option might be to build a 4.625 by 4 inch 532. It would have a little better piston speed than a 4 250 Stroke motor plus it would work with my 2.125 headers. I'm thinking maybe 50 or 75 more horsepower. Enough to give me a little more top speed without having to completely redo the combination as everything works pretty well right now. What do you guys think? Would you go something like this or just go ahead and build a 1200 horse 583 or something and start over basically?

Re: new super street engine
 

Personally I like the idea of keeping a small bore big stroke, if anything happened you still have room to bore.
middle of the pack is not a bad place to be. if you get going too fast it becomes hard to judge the very slow.
one other issue with going big inch is everything else in your driveline has to be bulletproof

Re: new super street engine
 

Assume you’ve got a fairly heavy car (my Super Street Avenger was right at minimum and only had 600 and could run 137); lightening the car yields the same results and helps with reliability and can possibly make it react faster, depending on your setup of course.

Re: new super street engine
 

I wouldn't let the headers dictate your plans. I'm a big fan of small headers; they won't blow up the dyno sheet but always seem to ET well relative to the measured power.

The 632 in my dragster only has 2.25" headers and is an underachiever at 1020 HP, but all the other guys going 8.90 at 180+ seem to need 1200+ HP to do it and I'm in that club.

I'd probably go with the longer stroke; more torque to get that car moving off the stop. And the smallish headers will help with velocity at lower RPM. Same with a smallish carb.

Re: new super street engine
 

the car is 3150 with me. it also sets a bit high and has the aerodynamics of a similar sized brick. i plan on lowering the front a bit this winter. wanted to let the new springs take a set before cutting them. I thought it would be faster than it is to but I'm sure it's the car and not the engine. It has a 488 rear right now and is going through the traps at about 7400 RPM. I've tried a couple of different converters. Right now I have a very consistent car in the 60 and im extremely happy with how the car drives. i can fab another set of headers if i need to just trying to keep it simple. i definitively agree with staying on the small side with pri tubes.
i talked to you this last weekend in great bend tony. i have the dark red 70 chevelle. thats an awesome nova you have.

Re: new super street engine
 

I knew you had some posts on the forum at the time we spoke! Great to actually meet you, and that Chevelle is extremely nice! I've never seen a car that said "Wagner's" on the door that wasn't mint.

Re: new super street engine
 

Go big or go home.

Re: new super street engine
 

I did not know MPH won races in the .90 classes ?

Re: new super street engine
 

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Re: new super street engine
 

There is a huge benefit in air flow with the larger bore size although I would go to 4.600" ,the additional .025" would be insignificant .
I would go with the 4.250 stroke and a .400 long rod. ….This has proven to be a good combination for making power thru a very wide RPM band .
On a car as heavy as yours , you will benefit from the 2 1/8" headers even with the larger displacement.
Just don't over cam it with too much duration .

Re: new super street engine
 

probably need to drop the gear from a 488 to a 56 if i went the quarter stroke route. the heads i have now are around 325 cc older brodix castings that flow 370 and 310. they are in excellent shape but im sure i would be leaving a bunch of power on the table if i used them but consistency is the game so i bet with the right cam using all the old stuff would work fine. prob make 950 and a bunch of torque. i know that speed doesnt nec win races but being a little closer to the 150 plus guys would help me judge closing distance a little better

Re: new super street engine
 

I'll take big bore/short stroke over the other way around everyday. My 522 4,560 bore/4.00 stroke makes 947HP with a 4150 carb atop it's small plenum manifold in my 3150 lb. Firebird. The plan is to run S/ST next season and I expect 150MPH on the stop.

Re: new super street engine
 

[QUOTE=gnicholson;574346]Right now I have a very consistent car in the 60 and im extremely happy with how the car drives. i can fab another set of headers if i need to just trying to keep it simple. i definitively agree with staying on the small side with pri tubes.
[QUOTE]


If the car is very consistent why are we making changes? Is the engine worn out or do you just want to go faster?

Re: new super street engine
 

mostly i would like the car to be faster. i dont have to be on kill but 142 to 45 would work

Re: new super street engine
 

I feel your pain Gary. However I keep reminding myself that a dial-able and consistent car will win more rounds. I sure do get tired of those cricks in my neck from looking behind me though, lol.
Let me know what you end up with. Maybe you can save me a few thousand dollars trying different stuff...

Re: new super street engine
 

Why do you have a crick in your neck. I thought you ran .90's without checking up?

Re: new super street engine
 

^^^ true that. man that car is deadly
Back to the original post I have won just as much in a slower car as I have being the faster car but given a choice I would always prefer to be faster

Re: new super street engine
 

I had the same 505 combo in my S/G Camaro. I went with a 4.500 bore with the rest of my parts in the new block. It is a 540. The increase in bore size and the 4.250 stroke work great. I picked up 6 MPH on the stop. HP on the 505 was 835 and the 540 is 870. This is on a tight dyno with real numbers. I would buy pistons and a block and call it good. Some flow bench time dont hurt and I ran mine up to 14.8 from 13.2 for compression.

Re: new super street engine
 

6 mph is a good gain. it had to have picked up more than 35 hp

Re: new super street engine
 

Certainly you don’t need to be fast to win....but if you’re buying new parts....you should probably make it big as you can afford...you can always de tune it....

I may not be a good example...lol

Re: new super street engine
 

Along time ago, a friend told me that if there isn't a penalty for cubic inches, get as many as you can.
Dan