IrocChuck

Hello,

I’m sure this question is out there already but can’t really find a good answer. Have a 89 IROC with a 700r4 and a 350 originally. Someone previously swapped a 305 into it. I want to put a 350 back into it. Any GEN 1 smallblock will work and bolt up to my trans? Or do I need to look for certain casting numbers that work better than others?

Thanks guys!

dmccain

iTrader: (2)

Id make sure I got an 87 or later 350 and one with a roller cam. Truck motors didn't go roller to 96 or so with the Vortec 350. Third gen 350s and some Caprice, Cadillacs or Roadmasters in late 90s also had roller 350s.

sofakingdom

iTrader: (1)

Yup, best short block to get, is the 96-2000 truck one.

For heads, choices are more limited. Any heads will "bolt up" EXCEPT the 96-2000 truck ones... the ports don't come close to matching your TPI manifold. "Drill bolt holes" doesn't make them work. You can buy the $$$Vortec base$$$ to fix this. IMO a PHENOMENAL waste of money, but to each his own, I guess. A Stealth Ram costs about the same, but replaces the ENTIRE TPI system, and will DRASTICALLY outperform TPI.



Or, you can find actual TPI 350 heads, which are casting # 083. Same casting was also available on some marine motors and some over-the-counter replacement ones. Best bet is probably a boat junkyard; look for late 80s / early 90s "260 HP" Merc I/O motors with busted (frozen) blocks. You can use 350 TBI heads (87-95 truck, Caprice, etc.) but they will restrict engine performance even more than TPI already does.

IrocChuck

Thank you for all the information! Are there any aftermarket heads you would suggest?

Fast355

iTrader: (2)

Some of the boats and over the counter 083 equivalents had a casting number ending in 217.

Homer0310

I am in process of putting a 75 truck motor into mine, trans bolts right up but all the little things that you don't think of. I had to use 153 tooth flexplate, 168 isn't drilled right for converter and I believe it would hit bellhousing .so I buy a the flexplate, get it on get trans in and go to bolt starter up and the gear on starter is like half inch from touching the flexplate. I didn't realize the staggered bolt pattern on the starter is for 168 tooth 14" diameter, the straight across pattern is for 153 tooth, sooooooo there is not many options for a starter without spending $300 .That has been my experience doing the swap, not too bad but makes a guy think haha, when I get starter I'm good to fire mine up

Homer0310

Oh yeah, forgot power steering hoses, the pumps are the same but bolt up differently, had to use the truck power steering pump, but hoses are different. Need adapters the go from old style to the metric ones in our cars

sofakingdom

iTrader: (1)

That's why we use 96-2000 blocks instead of 70s crap.

And of course, why we drill the block for the late-model starter pattern, BEFORE installing the engine.



This photo is a 73 or thereabouts 400 block that I drilled about 30-some years ago.

Since the inboard bolt hole of the early-model pattern would have to go RIGHT DIRECTLY THROUGH THE MIDDLE of the 12.8" starter drive, there is NO POSSIBLE PHYSICAL WAY to put a late-model starter for 12.8" wheel on a block that has the 14"-only pattern. Repeat, the problem isn't the starter; it's THE BOLT. The center of the late-model starter is about 5/8" closer to the crank (14" - 12.8", ÷ 2). There was at one time somebody that took a late-model nosepiece, machined off a chunk of it, and made up a mating piece that filled in the notch, that had a countersunk bolt at the early-model hole location that took a short bolt holding it to the block, and a place with the right hole for the late-model pattern. If memory serves, it was about a $400 solution to a $1 problem, when the problem is created SOLELY by lack of research, foresight, and planning. IOW a $399 dumbass tax payment.

Take your motor back out, drill the hole, and drop it back in.

THen next time, use a 96-2000 truck block. There are other benefits as well, too numerous to mention.

Tom 400 CFI

Should bolt right in, '91 or older 'Vette, '87 or older everything else...