Afternoon all. I need some help here. I have the opportunity to build my first motor for a 1987 Camaro Z-28. My car currently has the 305 LB9 and runs like a champ, but since I have the opportunity to purchase a 1988 350 out of a GTA for $400 (includes ECM, Exhaust Manifolds, TPI intake, runners, plenum, fuel rails, injects, cast iron heads, ect) I can't pass it up.

What I am looking to do is build a 300rwhp 350 TPI that keeps the factory L98 look, with a bit more polish, of course. The block is going to be stripped completely and sent out for checking and machining. What I am looking to find out is what I will need to do to the heads and what kind of cam to get for this build. Assume that I am going to port, polish, and port match the TPI intake, runners, and plenum. I am looking at a dual 58mm throttle body, 22 - 24lb injectors, shorty headers (as I don't think the long tubes will fit), and exhaust. A custom tune will be performed once it the motor is built and running.

This is my daily driver, and not a track car. I just want some extra umph while driving and the right to say I build a 300rwhp motor for my car. Any insight you can provide will be greatly appreciated. I spend a lot of time on these boards reading your inputs and I have found it very helpful.

 

You don't need a 58mm Throttle Body. 52mm will be fine.

 

Pass it up, and stick with the 305 that runs like a champ. My TPI-305 makes over 400-RWHP at 8-psi of boost pressure, and roughly 280-300-RWHP naturally aspirated w/under 9.0:1 compression. Your goal is more than doable with your 305, and since you stated that it runs good, then why get rid of it. Hefty mods wil be needed, but hey, you won't need to pull your engine out to do them. If you live near or around East Brunswick, Old Bridge or Woodbridge, I'll show you what a 305 can really do, especially at 15-psi of boost pressure, and you won't even care about that L98 anymore...

 

To get to your 300 rwhp, Vortec heads will probably be the most effective and most budget friendly heads. They'll probably be cheaper than reworking your current heads. But then your lower manifold won't work and a correct one runs roughly $400. That doesn't include cost of runners and time/skill of porting it all out, which will still be limiting hp due to the way a tpi works. A HSR will easily get you the hp you're looking for but won't be your planned 'stock' look.

Or just cam it with something like a 8-501-8 comp cam, exhaust, and you'll have a easy 250 rwhp with no fuss. That's pretty much what I run and if I switched to a HSR I'd open up quiet a bit of hp. A better questions for you is how much do you want to spend? How important is a stock look? How important is the magic 300rwhp?

Or listen to Street and boost it.......

 

No no, I don't want him to boost it. If he ups compression closer to 10.0:1, and gets a very good cam and head package like you just suggested, then his goal is more than doable. Only problem with the TPI is he will need to spin high RPM to make that power, and the HSR like you suggested would be a perfect fit. I siamesed my TPI setup which helped tremendously, and spins over 6000-RPM easily, but if I had to do it all over again, I would go HSR all the way, way too much porting involved, but paid sweet dividends in the end...

 

I was just being sly and giving a nod to your creation. I agree he could stay with his good running 305. Unless there's something wrong I'd just drive it, make if faster when it breaks.

 

Thanks for the responses, guys. I appreciate the info. The 'stock look' is pretty important to me. I am not looking to make monster power or anything, just get a bit more power out of the car. I am not running it at the track, or street racing it.

The reason I am building the 350 is two-fold. The first of these reasons is that I have always wanted to build a motor, and finally have the chance. The 350 is the most readily accessible motor to build and has the most information about how to build it available. The second reason is that the front seal on my 305 is starting to go. I know this is not cause to change out a motor, but with the opportunity to build a 350, I figure "why not?".

It is also my intention to keep the 305, as the numbers match and its original to the car. I will probably re-build that to completely stock specs once I get the 350 in.

Money is a bit of a factor, but lets say that I have a decent budget to work this 350 to 300rwhp.