Hi, the original 305 tpi motor in my 91 z28 died and I’ve been looking for a replacement engine and I have decided to upgrade to a 350 instead of buying a rebuilt 305. I have only been able to drive the car 6 times during the year that I’ve owned it so I’m not really looking to make a lot of horsepower, I’m just looking to be able to drive my car again and have a little more torque + horsepower with decent driveability.
The engine I’m looking to use is the gmpp base 350 h.o. with vortec heads. What I ideally would want to do is just swap that motor in place of my 305 re-using all the old hardware(pulleys, balancer, flexplate, distributor, engine mounts, exhaust manifolds, etc..) drop in a SD vortec tpi manifold to use with the new heads, put in 22# injectors, a 350 eprom + knock sensor and be on my way having a good running strong engine. I know that in order for me to be able to pass emissions where i live I’d need to use SD’s external egr kit. but I’m more worried about everything working/running correctly and I think I can install that later. I know I won’t get the advertised Horsepower of the engine with the stock tpi but I will upgrade it all once my budget allows it.
But that seems a little too easy, and lately everything I’ve read about the head + engine swap makes it out to have more headaches than what i thought. I’ve been told it will idle like crap and I would need a custom chip burned just to be able to have it run . Also would I have to bypass the water pump and grind the new intake to make the oil pressure sensor fit as well as plug up a lot of holes that are cast in the manifold that I won’t need for my application. Is this true? If I do have to do this, is this a lot of work? What kind of water pump would I have to use? I'm on a tight budget as it is so would it be less of a headache to just swap in a pair of stock/replacement heads and would it run better? Am I missing something important here? Do you all think that this is a worthwhile swap with minor hassle? Sorry about the long post. Thanks.
-EriC

Welcome aboard.

If I were to go the Vortec/TPI route, the only way I would consider it would be with the SDPC Vortec TPI crate engine. But, of course, that drives the cost up because there is still more it doesn't come with that is required.

The base HO would probably work okay with the TPI upgraded to 350 standards, but the SD TPI probably wouldn't like the displacement increase (or 350 SD like the cam difference), so PROM burning should be assumed. I still haven't heard what system SDPC used to get their 360 HP Vortec TPI numbers, but I'm assuming it was MAF.

I've heard (and the SDPC website says) that grinding of the Vortec TPI base for clearance is required to get it to work with whatever your combination is. With stock runners and all, shouldn't be much.

The base HO doesn't come with a water pump. Reuse your existing (or even better, get a new one for your current application to put on the engine when you put it in).

Oh, I doubt you'd need the EGR kit to pass emissions. If it's just visual, have a valve sitting on the base (if they know what they're doing, they'll fail you for the Vortec heads, anyway). If it's just sniffer, the cam should have enough overlap not to need the EGR to pass NOx.

But, you may need it...

Thanks for your reply i really appreciate it. I like the sdpc vortec 350 but its out of my price range. I kinda figured that i would need a custom prom for optimal performance but was hoping that the combination was not radical enough to make the stock prom programming unsuable. The grinding that is required doesn't sound like much work according to their website so i'm not too woried about that. I would just need to grind away excess material so that everything fits together snugly correct? What kind of water pump would i need for my application? Is it a different one other than what the engine originally came with or is there a water pump specifically designed for engines with vortec heads? As far as emissions go where i live, there currently aren't any, but i'm sure that will change in a year or so. but there was no visual just a sniffer test iirc. i will probably install the egr kit later just to be on the safe side. But all i really need to make this work is minor grinding for clearance/Better Prom/New Water pump and some tuning? anything else i'm missing?
Thanks again i really appreciate it.