1989mull-et

Let me start by saying I did a search and cant find what I need to know. I have a basically stock 1989 iroc. It has exhaust and 350 injectors in the 305. Runs good but has bad valve seals, I think. It smokes occasionally on start up. Engine has 68000 mile on it. This car is a manual. All that said I have a high mileage 1986 350 out of a pickup in my shop and I'm thinking about rebuilding it and using my tpi. Will the tpi work on 1986 engine and what will need to change.

GeneralDisorder

iTrader: (1)

Unless you do considerable improvement to the 350 (heads, cam, valve train, etc), the 305 that you have makes more power than that 350 does. The 89 305 LB9 was about 215 HP. That 86 truck 350 is probably about 170 HP. Either way you WILL need to tune it, and it should be tuned already for 22lb injectors on a 19lb ECU.

If you want to use the 350, the TPI lower intake will be wrong - wrong intake bolt angle. And some of the holes for the serpentine system brackets don't exist on the 86 heads and will have to be drilled/tapped. You will of course need the matching 350 knock sensor, and a proper tune. Which even a stock L98 tune will be wrong with the truck heads and lower power of the truck engine.

GD

1989mull-et

I was going to rebuild the 350. Add a performance cam maybe rockers little higher compression pistons. Nice street build Just wondering about the heads like you mentioned. So on a rebuild I would need some new heads and computer set up for it. Thanks

GeneralDisorder

iTrader: (1)

Honestly you are better off just picking up a good used Vortec for a few hundred. My 350 Vortec with cam, valve train, and careful blueprinting is 400 HP. The Vortec pull-out was the cheapest part of the whole build. $200 and they loaded it for me.

GD

1989mull-et

I really like the look of tpi. Will a tpi mount to vortec heads

GeneralDisorder

iTrader: (1)

Yes with the right manifold base. SDPC sells the Vortec TPI base.

GD

five7kid

iTrader: (14)

Those '86 truck heads are really bad. The most useful they will be is to prop your garage door open on hot days.

The 305 heads on a 350 truck engine usually work out well. A quick rebuild of the 305 heads is all they likely need. They would then bolt up to the 350 block and your TPI would bolt right back to the heads. The smaller chambers of the 305 heads will help boost compression back up (assuming you keep the dished truck pistons in the 350).

The biggest disadvantage of the '86 block is it won't accommodate roller lifters like your '89 has.

The Vortec longblock would solve both those problems, although as mentioned you would need a different TPI base. I've seen more than one Vortec 350 that lost rod bearings, though, so unless your engine happens to have a warranty, I'd go through any junkyard Vortec 350 I was considering buying.

GeneralDisorder

iTrader: (1)

Have to be careful because Dexcool ate the intake gaskets on all the Vortec's - mine came with milkshake in it due to a failed intake gasket. Fortunately in my case there was no real damage - none that a rebuild didn't take care of anyway.

GD