Hey everyone-
Got some questions answered on the 383 powerplant earlier...however, when flipping thru the forum, I notice guys are making almost as much horsepower (as compared to a 383 longblock) by changing heads, cams, and opening up the exhaust.
If I decide to re-do the bottom end on my car, go .020 or .030 over, and go with heads and cam- what is the recommended cam profile to reach the 400-450 hp mark?
I was thinking of going with TPIS AFR heads, which are supposedly a little massaged. What happens then with the cam? I want to be able to drive the car, although it will only be a weekend warrior. What headers and exhaust are the norm?
Also, what about reprogramming the PCM (?). Can this be done with a program and laptop, or does in have to be done out of a facility, or what? Any links to info or places that sell the programmers would be great.
I like Golens 383 package, which comes with the computer prgramming for that particular combo (with provisions for headers, cat back, etc) specific to your car. When looking at these swaps, whole engines or cam/heads..the computer programming seems to be the fly in the ointment for the "everyday Joes" like me who don't have access to hi-performance shops close by.
Thanks in advance for any info or suggestions. Love the forum!

 

There's nothing magic about a 383. It's a long stroke 350 with a 0.030" overbore. As with all strokers, the gain in hp is not proportionate to the gain in displacement because the heads and intake will only flow so much air. Torque gains do tend to be more in line with the ~9% displacement increase though.

As with any stroker, all other things being equal the rev limit will be less than a motor with a shorter stroke. For the way most street motors are setup though, the stroker can rev high enough anyway. The cams, heads, and intake can't support extremely high rpm and the stock PCM can't control the injectors above 7,000rpm. So the lower rev limit for a stroker is more of an issue for a race setup.

So, a stroker makes sense only if you are replacing the rotating assembly anyway. Since most high performance buildups involve a new rotating assembly, most buildups are strokers since the downside is not significant in a practical sense and there is some upside. None the less, a properly built NA 350 will make nearly as much hp as comparable stroker.

Out of the box AFR heads aren't worth the money for an NA car. They need porting to reach their potential and are therefore a lot more expensive than porting and rebuilding the heads you have.

Tuning is a whole nother thing. In general, a package doesn't sound like a bad idea if you have no access to other resources for tuning. But as to the particular package you refer to, I don't know anything about it. All you need to make changes to the flash program in the PCM is a computer, a cable, and software. I prefer LT1_Edit from www.carputing.com but others use Tunercat. BTW, you really don't need a laptop. For a while I was just lugging my desktop out to the garage.

Good luck.

Rich Krause

 

TPIS is pretty pricey.

I would check into buying the heads straight from AFR and then having someone else clean them up. You don't really need to port them much at all unless you're doing a big cam. Just clean them up a bit.

Strokers just make your car more drivable with a larger cam and give you a bit more torque. The horsepower is still made from the heads and cam.

 

Thanks for the detailed reply, Rich.
The Golen package I'm referring to is the 383 assembly that has Keith Black pistons, 11.0:1 compression, AFR ported/polished heads, and a TPIS 226/226@.50 cam. It makes (according to the dynos they sent me) 480 hp at 6300 RPM's. It comes ready to add my intake, injectors, Optispark, etc and also comes with a preflashed (or reprogramming your own PCM) in the package.
I have a price of 5600 delivered to my door. Not bad, when I have seen others do it themselves and have almost 4500.00 in the engine kit and machine work alone.
I agree with you on the shorter stroke, though..and would love to make the horsepower and keep the factory stroke.

What would you recommend- dropping a new crank, rods and piston assembly into my reworked block- going to a ported AFR (or similar) head, Throttle Body, etc- or just going to a 383?

Any suggestions on crank and rod brand?

 

If you're staying a 350 I would just consider maybe getting forged pistons.

If you're going 383 it depends on whether or not you will be using a power adder.

I went with a Scat crank which is good for over 700hp.

If you're looking for one of the strongest cranks you can go with a Callies Dragonslayer from www.nu-tekmotorsports.com

Eagle H-rods are pretty decent as well for connecting rods.

 

Thanks Gripenfelter-
Is the stock crank forged? Is it stout enough to handle 400+ HP?

 

When you throw out numbers like "400+ HP", are you talking rear wheel HP, or flywheel HP? The stock cast crank is easilly good for 500 flywheel HP, as are the stock rods. A set of hypereutectic pistons will hold up to that HP level as well. IMHO, you only need forged components when you start talking "major power adder". Put the money into healthy heads and cam, and save $$$$ on the bottom end if you are sure you will stay normally aspirated. Since you already have some good LT1 heads, just get them ported for the best "bang for the buck".

 

Injuneer-
I'd like to be around 400-425 RWHP.

I'm most likely going with forged pistons, crank and rods..just for the sake of things.
I was told to shoot for around 10.5 to 11.0 compression..sound about right?

 

In your case, since I'm assuming pump gas, the optimum compression ratio will depend primarily on what cam you use. If you go for a big cam, you will need a higher compression ratio. Like Fred (a voice of reason!) said, your best bet is a stock bottom end with a good heads and cam package. I don't see how you would want to spend ~$2,500 just for the sake of things. If you want to do it though, it's your money.

You could see ~400rwhp just with a decent cam and heads plus headers and an exhaust system. But if it's just a "weekend warrior" and you have the $$$ to spring for complete rebuild, why not aim higher? I am just having a hard time figuring out what kind of a car you are building.

Rich Krause

 

Hi Rich-
First off, I'll try and explain my vision for my car.
It is a 94 Z, with around 100,000 miles on it. Its in decent shape, but needs a new interior, new paint, and of course the motor.

I plan on lowering the car, putting new springs (aftermarket, 18" rims and tires, a ground effects kit, cowl induction hood, and possibly a SS rear spoiler or something of the type. Its a project, an experiment. And, it is a more interesting project than the 52 Chevy truck I had planned.

I just want a bad-a** Z, to put it mildly. A "look at this" car.

Given the fact I build and paint 50-60,000 dollar Custom H-D's for a living, I don't do anything halfway. So, as far as the motor goes in the car..yeah I agree with you on keeping the stock bottom end and keeping thigs simple- but given the fact I'm paying to machine it either way, and will have to reassemble it...why not spend the money and KNOW I have the best parts in there? Over-doing it? Yeah, no doubt. But its really a "toy" so I don't mind spending the money.

These new motors, with the electronic stuff on them are a different animal than what I am used to- so thats why I am trying to get as much feedback as possible.

Thanks again for the help.