Ok my car has some subframe issues and suspension problems, Plus its lack of overdrive is really gonna kill my 6 hour commute to school next year. I have a guy that has an 86 IROC with a 305 TPI and a 700R4...I thought it might be a good idea to swap all my good stuff, Custom interior, billet grill, stereo, and possible motor stuff. All my exhaust from the motor back. The 305 TPI has a main bearing gone so the bottom end is pretty much trash. I am looking for options of using my bottom end in this car. My motor is a '78 4 bolt main block with .30 over 10.1 pistons and a decent cam.Heads on it arent really anything special. What are my options for the swap. I would really like TPI since this car already has the computer and stuff. Could I use toe 305 heads and TPI unit on my 350 block? Or would it kill alot of power? What all is involved with the ECM if I found 350 TPI heads and intake and bolted them to my motor? What about a complete 350 TPI motor out of another car, What all is involved with that swap. Also If I use my bottom end, Wont I need a new flexplate? Since my motor is older? I know ALOT about these cars, But know very little about TPI and computer controlled stuff on these cars...Thanks for any help!

 

I do not believe that you can use 305 heads. The 350 TPI heads should bolt on.

 

So should I look for a set of 350 TPI heads and and the TPI unit? There isnt anyway to do any modding to get a TPI unit to work with older heads is there? If I get 350 TPI heads and intake, What would I have to reprogram? What extra stuff would I have to hook up and do to my old block? My current motor has no emissions stuff except a cat. No O2 sensors no smag pump, Nothing...My headers have 1 O2 bung in them? So should I try to find a set of TPI heads and intake or should I try to find a complete TPI motor and sell my 350 I have now?

 

1986 Irocs were a hybrid year. The heads are perimeter bolt valve cover type like the old style, but the block is a 1-piece rear main, like the newer ones. Why not just use your block and heads with the Iroc TPI? I don't know about the TPI intake bolt holes being a perfect fit with your heads, but I hear the holes can be easily elongated to fit (that is IF they don't match up). But since the '86 had old style heads, then they should be the same as the ones on your 350. I would not use the 305 heads on a 350 as it would choke that 350 down, plus you'll raise your compression even more. I am using a '79 block in my '86 Iroc with centerbolt heads. You'll need to use your old starter and flywheel. You will probably want to do a cam change, also, to better accomodate the TPI. You'll need to burn or have a custom chip burned. You can get away without burning one for a while, but eventually plan on doing that. Bigger injectors, too. Stock were 19 lb/hr. I'm using LT1 injectors (24 lb/hr). Buy a used set for $50-$75. An adjustable fuel pressure regulator wouldn't hurt either. As far as chip reprogramming goes, a promising new option is the prominator, check it out.... you can hook up a laptop and just upload and upload and upload different binary files as many times as you want without having to mess with actually burning chips.
http://misterbill.homeip.net/aboutprominator.asp

 

305 TPI heads that have been ported and had 1.94" intake valves installed will flow as well as L98 350 heads. You just need to watch the compression ratio (58cc vs. 64cc chambers). A thick composition head gasket can resolve that issue.

The only differences from the factory between 305 and 350 TPI setups were injector size (19 vs. 22 #), regulator (you should just go with an adjustable, anyway), PROM tuning (you should figure on doing your own PROM burning/tuning, anyway), and knock sensor & module (which you should change to 350 if installing a 350, anyway).

 

So your saying the 305 TPI unit on that car now would work on my old sytle heads with a little mods? Think I could get all that to work out by myself? I really dont know much about newer motors and stuff...Where is the fuel pressure regulator on these cars? Where would I install the knock sensor on the older block? My old starter and flywheel are from the truck that my motor came out of, Since I have a TH-350, and barely clear the bellhousing, Will these work on the 86' 700-R4. And how much of an issue is getting a chip burned? Also what cam should I consider? How much of an issure is installing injectors? Like I said, I know old school stuff, just not the newer....Thanks again guys!

 

'86 heads are old-style. Therefore, so is an '86 TPI intake system base.

The fuel pressure regulator is on the fuel rail.

The knock sensor goes in a block drain hole that's been in every SBC since 1955.

Use a 3rd gen flywheel and starter, assuming the 350 engine has the proper mount bolt holes (which it should).

There's a forum dedicated to the PROM burning issues. Check there for that (just don't go begging for the actual work - they hate that).

Use a computer-compatible cam. Unless you do significant TPI system mods, keep it fairly mild. For example, a Crane 2030.

Changing injectors is a little harder than an oil change, quite a bit easier than building a thermo nuclear device.

No time like the present to learn.

 

A) Call Comp Cams tech line to get their recommendation. Just keep in mind their recommendation might be a little conservative IF you ever plan on adding more mods to the factory TPI intake system. So if you ever plan on getting bigger intake runners, porting plenum, heads, blah blah blah, just leave yourself some room to grow. If you will not mod it anymore, then use what they say. Check out their Xtreme Energy line XE262, XE268, XE274 depending on what you plan to do in the future. They recommended for mine the XE262, I got the XE268, and wish I had the XE274 (at the time I didn't plan on getting a Holley Stealthram and Trick Flow heads).
I don't know if the other cam manufacturers have tech lines, but if they do, call them if you don't want a Comp Cam.
B) It's not hard to do. Just post questions here. I would have had a tough time if it weren't for this board.
C) Programming will probably be the toughest to figure out, but I don't know cause I haven't got around to that yet!
I don't know which heads you have right now but some guys around here have shown that if you port the L98 350 TPI iron heads quite a bit, they flow really well.

Five7kid,
As far as the starter and flexplate goes, I bought a new flexplate and then my '86 305 starter wouldn't fit the older 350 block and flexplate. I'm not really sure whether it was because of the different flexplate or the older block (Remember the '86 is a new block). Can't he just use these parts off his old engine (from the 350)?

 

Today I was looking through jegs and got a few questions? Does anyone have a suggestion on which adjustable regulator would be good? Also, Is there anything cheaper when it comes to injectors...The cheapest in there were the accel and they were still $220, Also, what pressure should I get, I was thinking 24lb but really dont know which would be best. Another question...I have a 3 guage pod in my present car with mechanical oil psi, temp, and amp...Should I just use that in the IROC or should I get sensors to hook up electrical guages....My car is old school all the way with nothing computer on it, So anything else I would need to worry about in the swap?

 

I'm doing a 383 stroker build for my 88' T/A. I found brand new 24 lb injectors on E-Bay for 140.00, and I payed too much. They will usually go around 100.00. Actually you'd be suprised how much stuff you can find on E-Bay, give it a shot.

 

If I just swapped the 305 TPI setup on and didnt install adjustable regulator, injectors, or a prom, Would it be drivable? It would kill power I know, But it wouldnt hurt anything until I could save up some more to buy the other stuff would it?

 

You probably will be OK. But I guess it mostly depends on how well the cam and computer get along. Another thing you might want to watch out for is the mixture. Now I haven't tuned mine and I do have some problems with it searching for idle sometimes (idle up and down until it dies), but it is driveable and I'm running an air/fuel ratio guage on it and the computer seems to compensate fine.... all this with the 305 chip. The oil sending unit on that car is actually two, you must have discovered when you did the swap. One goes to the computer (from what I've read) to cut off the fuel pump if you lost oil pressure, so that one will have to remain electrical. Something you might want to look into. Buy an air/fuel ratio guage to see what is really going on so you know you're not running lean and hurting your pistons. I have a BBK adj. fuel pressure reg, but I haven't put it on yet, so I don't know which one is the best. Like I said, I bought a set of LT1 24 lb/hr injectors for about 50-60 bucks (used).