Small Block HP - How Much?

[jmarsey]

Originally posted by aumoore
My 302 is a stock explorer long block with stock GT-40pheads, trick flow stage one hyd roller cam, edelbrock performer rpm intake, Holley 600 vac secondary and the Hunter 4 into 1 headers. On a chassis dyno it put out 267hp and 285 ftlbs to the rear wheels. If you use a conservative driveline loss of 15% that is 315 flywheel hp and 335 ftlb's at the flywheel. There were several aluminum head motors at that dyno day and There was a 289 that put out just under 280 hp to the rear wheels. The Stroker motors were running from 300 to 313 rear wheel hp.

A 540hp 302 with no power adders would sound like a late model dirt track motor or a drag motor. It would make a terrible street motor. Now a 460 could make 540 and be pretty docile but even then you would know it is not stock.

aumoore,

The point is, is it takes quite a bit of tweeking to get serious power from a 302 with one four barrel. You are correct in that my motor would not make the ideal street motor but then it wasn't designed for that purpose. My motor was designed and built for road race events. And believe it or not, it is pretty conservative. You would be surprised how docile this motor actually is. A Late Model motor is a whole other animal entirely.

[Tom White]

I doubt that much HP can come from a "streetable" pump gas 302. Mid 400's with a aggressive cam, cnc'd aluminum heads, balanced, blueprinted etc is about all you get. After that you need extra help. TW

[Mr.Fixit]

It takes a good deal of development to get a pump gas ~400 cid windsor to make an honest 500 hp with a single holley on a vic jr. Been there and done that, so a 400 hp 302 is the expected borderline between radical street motor and race motor in a street car. After about 1.2 hp/cid it gets tough and expensive.

[Jeff Frigo]

How much hp on the small block? Don't know, but a big block will have more.

[RACER X #99]

All Nascar Road racers have small blocks, all Trans AM Mustangs, Camaros, Jaguars, all have small blocks. All of them weigh more than Cobras and every single one of them is faster than any Cobra.

But a Big Block will win you a trophy at most car shows.


Big for show

small for go

[Jeff Frigo]

The only reason all of the cars you mention above run small blocks is because that's all the rules alollow. What did all of the Nascar boys run when bb's were allowed? Not small blocks. Why did they change the rules to small blocks only? To slow them down, the bb's were too fast.

[RACER X #99]

Frigo ,get real you better check the record books for the all time fastest Nascar lap.

40 years ago the only way to go fast was bigger, times have changed.

Of course Drag racing still does it that way but we all know that Cobras are not drag cars.

[Rick Parker]

Those in the know who work to develop the Hp we all covet will tell you that a REAL small block 289 will be done at about 510 HP with ALL the tricks for Vintage Car classes. No power adders, lots of compression using only OEM heads, no strokers, or nitrous. 1-4BBL Holley, lots of RPM. If you have ever been around one at the track you won't overlook it and they are often brought in for exceeding the decibel level at specific tracks, they love open exaust.

Rick

[RACER X #99]

Rick,
One of the guys we do open track with has a 289 Shelby GT350 that he races in Vintage Class. It is the LOUDEST car at the track. I will drown out any 427. Bigger may have more torque, may have more HP, may sometimes be faster than a small block. But louder.NFW

Cranky

[scottj]

Jeff- So lets look at a car that has no engine rules. Dirt Late Models have only two engine rules: No Ti rods and one 4 barrel carb, thats it. So why do you suppose BB's haven't been competitive in the class for twenty years, especially considering how much more power a single 4 barrel BB makes than a 4 barrel SB?
I'll note that as a younger kid I was first attracted to these cars because I was heavily biased towards BB's.

[MRITTER]

Well, I just had my 302 (ok 331) tuned last week on the dyno and it made 532 hp and 580 torque at the WHEELS. All it took was 2 turbos blowing 10 lbs, R block, systemax intake, 42# injectors, $1200 fuel system, etc, etc, etc, $$$.

I doubt that he was making 540 from a NA 302 that was that mild at idle.

Mike

[Wayne Maybury]

Cranky

You bring up a very interesting point. You say the SB is louder than the BB cars. I have always been interested in what is called the "big block sound". Personally, I have never been able to tell a BB from a SB by only listening to the sound of the engine.

I run a 357 cu.in. Windsor which produced 472 HP and 440+ lbs of torque on the dyno. (Real HP not BS HP ) Everyone that sees the car thinks it has a BB in it. They cannot believe their eyes when I open the hood to expose the Windsor power plant.

Mr.Fixit

My engine produces 1.32 HP per inch and I have to agree with you that much more than that would not make a very good street engine.

A 500+ HP street 302 with no blower or bottle doesn't add up. I have a feeling it is mostly BS HP.

Wayne

[RACER X #99]

Wayne,
I think we can all agree that the BB FE does have it's own unique sound expecially in Cobras. I attribute this to the not so racer friendly exhaust ports on the FE. A design flaw that canot be corrected just by simply porting or aftermarket heads. I read recently that a 1200 hp FE was created by someone using a new Shelby Block and Heads But the exhaust ports were raised similar to what they used to do to the Cleveland Heads before the redesigned Yates head. I'll bet this engine does not sound like a regular FE although 1200 hp does make noise no matter whose brand. If you redesign and raise the ports an a regular FE, what are you going to put it in? You might just as well build a 385 series engine.
The sb Ford with a much more racer friendly exhaust to intake flow ratio makes a different sound similar to the sb Chevy. Of course lots of Compression doesn't hurt the noise factor either.

When the FE fans say nothing sounds like a Big Block I have to agree. Not very impressive.( with apoligies to my freinds that really race their FE's)

357 ci 472 hp now that's impressive.


Cranky

[John McMahon]

..wait until youse guys hear my 351 with full length, muffler free 289 sidepipes.

[Sizzler]

Originally posted by RACER X #99


Wayne,
I think we can all agree that the BB FE does have it's own unique sound expecially in Cobras. I attribute this to the not so racer friendly exhaust ports on the FE. A design flaw that canot be corrected just by simply porting or aftermarket heads. I read recently that a 1200 hp FE was created by someone using a new Shelby Block and Heads But the exhaust ports were raised similar to what they used to do to the Cleveland Heads before the redesigned Yates head. I'll bet this engine does not sound like a regular FE although 1200 hp does make noise no matter whose brand. If you redesign and raise the ports an a regular FE, what are you going to put it in? You might just as well build a 385 series engine.
Cranky

That was an engine built by Shelby Enterprises. Haven't seen anything else on it since that one article. Did it blow up?

Never tried it, but in a Cobra, it might be interesting, for someone with a curious bent, to reverse the flow through the heads of an FE sort of like the old Gurney engine (either with Webers on fabricated intakes or EFI); intake through the 'exhaust' ports with the actual exhaust exiting through the 'intakes' over the engine valley. This would be an awesome engine for a GT40, in a Cobra, I could see the bundle of snakes exhausts coming out forward over the center of the engine into one large turbo.

Just dreaming.

[got snake?]

Originally posted by MRITTER


Well, I just had my 302 (ok 347) tuned last week on the dyno and it made 532 hp and 580 torque at the WHEELS. All it took was 2 turbos blowing 10 lbs, R block, systemax intake, 42# injectors, $1200 fuel system, etc, etc, etc, $$$.

I doubt that he was making 540 from a NA 302 that was that mild at idle.

Mike

mmmm turbos....ahhh...Love that whistle!

GS

[Wayne Maybury]

Cranky

I asked the engine builder to put together a strong "street" engine for me. Since I wanted good low rev throttle response, I decided to go with a dual plane Edlebrock Performer RPM intake. The builder choose everything else. He advised me that the dual plane intake would cost me some top end HP. The one thing that went on the engine that the builder didn't have a lot of experience with, at the time, were the Ford N351 heads. They are basically stock, not really ported, just cleaned up a bit.

When we dynoed the engine, the builder couldn't believe the performance numbers. Lots of torque right across the rev band and pretty decent power output to boot. This setup runs very well on the street using 94 octane gas.

Wayne

[RACER X #99]

Wayne, You are the first person I heard of using those heads. As you know these are the only heads that are approved for the strictly stock Sportsman Racing programs. These heads work so well that the brand X racers are always complaining about an unfair advantage for Ford (it's about time).According to what I have read these are the best flowing heads from either Ford or Chevrolet that are approved for Sportsman racing.It is amazing that Chevy ruled the Sportsman ranks for years until Ford deceided to get serious about the entry level series.
Sounds like you have built a winner.
Good luck with it,
Cranky

[Wayne Maybury]

Cranky

You are right, these heads really flow. As I said they are not really ported, yet the engine was able to put up some pretty good numbers. One big drawback with these heads is the bolt pattern for the exhaust, not the same as any others. I didn't care since I had to have custom headers made anyway.

I got the heads, brand new, from a friend of mine who races DIRT modified. He uses the same engine builder that put my engine together. Chevy powered cars absolutely ruled this track for many years. Then the Ford powered car took the championship 2 of the past 3 years. You wanna hear the Chevy guys cry. I guess they think they must always win.

By the way, Ford has now come out with N352 heads that have slightly smaller ports but reportedly flow just as well as the N351 heads. They are supposed to really work on smaller cube engines like the 302's. These new heads are in the latest Ford Motorsport catalog.

Wayne

[John McMahon]

This is Small Block Talk, right???? Why do these Big Block guys keep chiming in here???