Thread: TPI questions

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I have a '66 Chevelle that currently has an early '70s 350 in it along with a TH350. I also have a TPI setup from I believe was from an '88 or '89 Camaro that was given to me complete with computer and harness. I'm working on identifying it now. How do I identify it? I know it works because I heard it running on a 305 before I got it. My question is this. I want to use the TPI in my Chevelle along with a 700R4 I have. Will the TPI work on my present motor or should I get a new crate motor from GM? I have all the info on putting the 700R4 in, just need to know about the TPI. I will rebuild the 350, if i use it, before I install the TPI. I also plan on putting different gears in the rear end to go along with this TPI/700R4 combo. Any advice on what ratio? The car is just going to be a nice weekend driver. The car still has the original gears in it. The car originally was a 283 PG car.
Any and all help and advice would be greatly appreciated!
Thanks much!

The TPI will work....

The only thing is that you will have to chip the computer to be fully compatable....

Also to get the full potential if that tuned port came off a 305 and your putting on a 350 I strongly suggest putting the 350 sized injectors in it....Off the top of my head I think the 305 came with 31lb.hr. inj. while the 350 had 36lb.hr. injectors....

I would call JetChip on the computer issues www.jetchip.com and for a simple instalation harness call Painless Wiring.

good choice.....my two favorite things in life....TPI and 66 chevelles

Thanks for the help! How can I identify exactly which TPI unit I have? I know there will be numbers on the intake somewhere but are there any on any part of the TPI unit or runners? I also have been told that on some early 350 engines you have to enlarge and elongate the middle intake holes for the bolts to go through and seat properly. Is this an issue with using the older engine?
Thanks again!

A good summary of the history of GM Port Injection is at

http://www.fuelinjection.com/

Click on the "GM Port Injection" button. This article was written in about 2000 before Don passed away so it hasnt been updated for the later injections......

It briefly mentions TBI (throttle body injection).

Okay, I have heard that the TPI manifold has a different angle and won't bolt directly to the heads of a late 60's early 70's motor. Is this true? If so, can I use the heads from a TPI motor on an older SB? Ihave a 305 that the TPI came off of but want to use a 350, which is now in the car but with a carburator on it. Would I have to elongate the holes of the TPI intake to bolt up to the older heads? Any aftermarket heads available to use on an older block but using the TPI?
I know, lots of questions but I want a TPI under the hood of my '66 Chevelle and I want to make sure I do it right the first time!
Thanks again!!

sure you can do any of those.....mod the intake to fit or buy after market heads to use .....or find a 89 up TPI 350 and yank those heads (cheapest) the 305 heads on the 350 will be pretty restrictive unless you hog them out....your choice

Originally posted by dr_bowtie
sure you can do any of those.....mod the intake to fit or buy after market heads to use .....or find a 89 up TPI 350 and yank those heads (cheapest) the 305 heads on the 350 will be pretty restrictive unless you hog them out....your choice

Thank you very much! Do you or anyone else have any suggestions as to which heads would be best? As I said earlier this will be a weekend driver but I would like it to perform real well also.
Thanks again!

The 700/R4 isn't a computer controlled transmission - except maybe for the lockup, and you can handle that in other ways.

The best book on TPI is "Tuned Port Fuel Injection"
by Frank "Choco" Munday
this book covers everything you need to get up and running!

Post '86 chevy changed the heads so that the middle 4 mounting bolts go straight down instead of in at an angle - this is why your TPI unit will not just bolt on ( unless you change the heads too ). If you look at some aftermarket manifolds they are dual drilled for early or late setups, I have heard/seen people drilling the intake out so you can bolt it onto your existing heads. So theres an option.. or you colud find a '85 or '86 manifold base (which will bolt straight on ) and go from there.

Far as the electrics go you can get a harness from painless etc or there are a few guys selling them on ebay that make them themselves.

There are 3 main systems , '85, 86-89 and 90-92. The '85 is the most undesireable, the 86-89 is fine, but uses a MAF (air mass meter ) which you might not want under the hood ( can be kinda ugly ). The 90-92 is better in the looks department because you can get an air filter to just bolt straight onto the inlet.

What you could do is buy a 90-92 ECM, the sensors etc are *mostly* the same..

have a look at www.chevythunder.com - an invaluable resource ( the website owner is ne of the guys selling harnesses on ebay ).

I'm going through the exact same swap with my 78 firebird from a 88 firebird. I know that when i put my intake down on my heads the injestors overlapped a little. I talked to a coulpe of guys at the track and the told me to take a die grinder to the heads and notch it out a little since it was minimal. You may have the same problem you may not just a suggestion. Also have you heard anything about the vats system On these cars.

You can use the heads from a new motor on an old one, i did it in my 88 gmc truck with a 78 305 short block i had kicking around. The motor eventually blew a rod but had nothing to do with the heads, the engine ran fine and the gaskets appeared to be the same when i did it. it think the change in block design for the manifold not working was 85.?

btw, you may as well get vortec heads if your going to be spending any money on factory set of heads