Adding 100+ HP to this combo

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travis
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Adding 100+ HP to this combo

Post by travis » Sat May 05, 2018 1:13 pm

Not my car, or my build...just helping someone out.

357 sbc, unported 601 heads with stock 1.84/1.50 valves, 3 angle valve job, screw in studs, guide plates, and comp 986-16 springs, forged dished stock replacement style pistons, approx 9.7 compression, old SSI hft 302/302 advertised, 246/246@.050, .509/.509 lift, 108 lsa, 103 ica. Weiand 7546 with divider plate installed, 750dp Holley. 1 3/4” headers with full length 2 1/2” exhaust and flowtech terminators (sounds really good).

Car is a 1980 Camaro, TH350 with B&M 3000 holeshot converter, 3.42’s/posi, 235/60-15 street tires, and weighs about 3800 with him in it.

I did some fiddling with the timing, advance curve, and jetting. Best 1/4 mile is 14.01@97.35. The car will barely spin the tires on the street. It is a near daily driver and will not see the strip much at all.

The owner was nearly sick when the best it would do is 14.0’s...so much so that he yanked the engine and had it dyno’d. I don’t have the whole pull in front of me but it peaked 327hp at 5900, 344 lbs-ft at 4300 iirc. It pulls cleanly to 7000 but is seriously lacking in torque...especially for a 3800 pound car.

I’m sure gearing and head porting would make a huge difference, but the gears are fairly new and won’t be changed. He wants high 12’s on sticky tires and to be able to melt the street tires at will. Suggestions on how to approach this for under $1200-1500?

Fwiw, he loves the way it sounds, so he is reluctant to change the cam, but I don’t think I’ll have to twist his arm too hard

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Re: Adding 100+ HP to this combo

Post by cuisinartvette » Sat May 05, 2018 1:23 pm

sounds like you know the answer...those heads have got to go for sure

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Re: Adding 100+ HP to this combo

Post by groberts101 » Sat May 05, 2018 1:30 pm

His flavorite brand aftermarket 2.02 valved cylinder heads with smaller combustion chambers(even another -.040 flat mill wouldn't hurt with that cam), eddy airgap intake, and retune it. Not 100 horse gain but easily 60 plus and gobs more torque to better match those gears to help move that tub.

travis
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Re: Adding 100+ HP to this combo

Post by travis » Sat May 05, 2018 1:32 pm

Heads for sure. Would 170-180cc be enough? And would that get him there with that giant cam (for street car)?

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Re: Adding 100+ HP to this combo

Post by Scotthatch » Sat May 05, 2018 2:00 pm

groberts101 wrote:
Sat May 05, 2018 1:30 pm
His flavorite brand aftermarket 2.02 valved cylinder heads with smaller combustion chambers(even another -.040 flat mill wouldn't hurt with that cam), eddy airgap intake, and retune it. Not 100 horse gain but easily 60 plus and gobs more torque to better match those gears to help move that tub.
I agree

The heads you have are not worth the effort basic aftermarket heads have come way down in price you don't need great heads to be better than what you have and you can gain compression to boot ...

On a side note .....
Have you considered nos?

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Re: Adding 100+ HP to this combo

Post by groberts101 » Sat May 05, 2018 2:08 pm

travis wrote:
Sat May 05, 2018 1:32 pm
Heads for sure. Would 170-180cc be enough? And would that get him there with that giant cam (for street car)?
I'd be inclined to keep the volumes smaller in hopes it would make slightly higher AVERAGE power to help with that weight and tallish gearing. He needs better breathing for sure.. but velocity will help on the street and make it funner/more responsive to drive in its current config. 190's with a smaller chamber(more compression) probably wouldn't give up much though.

That dual plane wannabe isn't helping matters either.

And also run bigger base timing, slightly faster mechanical curve that has been heavily shortened to allow that bigger base number, and a heavily restricted vac advance pot tightened almost all the way up to only add another 10 or so degrees at idle and light load cruise when the engine will tolerate it. Cooler 160-170 degree t-stat and add more accellerator pump shot since that more aggressive timing curve will gobble it right up faster.

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Re: Adding 100+ HP to this combo

Post by B Original » Sat May 05, 2018 2:25 pm

I think a dart Iron Eagle 185cc port and Mill the chamber down to keep your compression or something similar. Your cam would work better with this as opposed to the 601s although a cam change might be in order to. I think your goal of a hundred horsepower is not out of the question at all. And would be easier to come by or probably exceed if you felt like you was up to the task of doing a little Port work while you're at it. I find 450 horsepower Plus should be an easy goal with head similar to that and 9.5 to 1 compression

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Re: Adding 100+ HP to this combo

Post by Carnut1 » Sat May 05, 2018 2:46 pm

Those heads stock are down right dismal. They also take a huge amout of work to get decent performance. They are also crack prone. A few years ago I worked up a similar casting 450's I think I managed 252 cfm. I doubt I would ever do it again. So much better iron or cheap aluminum to use.
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Re: Adding 100+ HP to this combo

Post by carzngunz » Sat May 05, 2018 3:05 pm

After reading through this I remembered a magazine article that was a similar build. I finally found it and thought it might be of some interest to the OP. http://www.hotrod.com/articles/0611em-v ... all-block/

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Re: Adding 100+ HP to this combo

Post by blykins » Sat May 05, 2018 3:07 pm

Cam is too big for what it is. Either put a smaller camshaft in it or swap heads to parts that will breathe. If he's wanting a street car, then I would highly suggest doing the former.

The duration vs. peak hp rpm should be a huge clue. You can hit that peak, keep the same horsepower, and make a lot more torque with about 20° less duration.
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Re: Adding 100+ HP to this combo

Post by GARY C » Sat May 05, 2018 3:30 pm

Yes, the heads or not right for peak power and the cam to big for the gear and converter combo, if the car owner is going to let how it sounds over ride the proper combo for his goal then you are fighting a loosing battle.

Going to bigger head with that cam is likely to make it even lazier with the gear and converter.
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Re: Adding 100+ HP to this combo

Post by PackardV8 » Sat May 05, 2018 3:52 pm

Get a new customer. This one builds a small-displacement engine with a low torque cam and junk OEM heads; then he's surprised he can't smoke the tires at will and run 12s. Then, he wants you to make all the above magically appear for $1500?

Since we're not up on best SBC pricing, just what is current retail for the heads, cam and intake recommended? Then, figure your removal and installation labor, plus the distributor recurve and tuning.
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Re: Adding 100+ HP to this combo

Post by lefty o » Sat May 05, 2018 4:03 pm

better heads, along with a cam that was ground this century (and actually matches the combo), and some more gear.

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Re: Adding 100+ HP to this combo

Post by Carnut1 » Sat May 05, 2018 4:08 pm

That intake is also terrible, I had one once. Gave to someone I didn't like.
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Re: Adding 100+ HP to this combo

Post by steve cowan » Sat May 05, 2018 4:53 pm

PackardV8 wrote:
Sat May 05, 2018 3:52 pm
Get a new customer. This one builds a small-displacement engine with a low torque cam and junk OEM heads; then he's surprised he can't smoke the tires at will and run 12s. Then, he wants you to make all the above magically appear for $1500?

Since we're not up on best SBC pricing, just what is current retail for the heads, cam and intake recommended? Then, figure your removal and installation labor, plus the distributor recurve and tuning.
jack hit the nail on the head (pardon the pun) cannot even buy a decent set of aftermarket heads here in Australia for $1500.
as said a 100 - 150hp of nitrous would be your friend here but if the guy has no clue how to use the bottle that is a can of worms in itself.

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