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gnicholson 10-04-2018 08:55 PM

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?

Keith 944 10-05-2018 09:08 AM

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

jmcarter 10-05-2018 09:37 AM

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.

Lenny5160 10-05-2018 10:48 AM

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.

gnicholson 10-05-2018 02:46 PM

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.

Lenny5160 10-05-2018 03:45 PM

Re: new super street engine
 
Quote:

Originally Posted by gnicholson (Post 574346)
i talked to you this last weekend in great bend tony. i have the dark red 70 chevelle. thats an awesome nova you have.

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.

Average Joe 10-05-2018 06:12 PM

Re: new super street engine
 
Go big or go home.

X-TECH MAN 10-05-2018 07:01 PM

Re: new super street engine
 
I did not know MPH won races in the .90 classes ?

X-TECH MAN 10-06-2018 09:02 AM

Re: new super street engine
 
quote deleted .........

Tom Goldman 10-08-2018 09:15 AM

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 .


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