spdracerIROC

Okay,


Here is the question:


As most of you know my 88' IROC *HAD* a 350 in it, but it was shelled and replaced with a very strong 305. (built up motor from a wrecked 305 car)

Anyway..... I have the 88 TPI Intake and everything on this 305, runs a bit rich, so I bet the 350 injectors are in the intake, and the computer was probably swapped for a 305 computer, if even swapped at all. I have the previous owner to thank for this headache.

Wonderful car, and blows just about anything without a big block off the road, but I want it to have a 350 as that is what it came from the factory with (I've ran the build codes to check)

So..... basically I need to know what year range I can use for a 350 without worrying about drilling new intake bolts or other BS.

I want to find a good block to start rebuilding and drop a 350 into my IROC like it is *SUPPOSED* to have in it.

All I want to do when I drop in the 350 is drop in the motor. replace the PROM and injectors, and wire up a 150HP Nitrous shot.

Any tips?

five7kid

iTrader: (14)

Block? Doesn't affect the intake manifold. Heads do. '86-older, the other type. '87-newer, the '88 type.

Flexplate, on the other hand - need to match plate & rear main seal type, no biggie. '85-older = two-piece, '86-newer - one-piece.

If you think it has 350 injectors in it now, why do you think you need to replace the injectors when you put a 350 in it?

You want to wire in a 150 shot, but don't want hassles? Sure-fire way to shell another engine. It may not be that big a shot, but using nitrous is best done with an engine built with that in mind.

spdracerIROC

Thanks for the tips on what to use for a block.

I was debating on whether or not to use the 305 heads on the 350 if I had them ported/polished and beefed up. There is quite the debate in some circles whether or not a 350 w/305 heads is a better way to go. Supposedly the upper RPM limit of a 350 w/305 heads is about 6200, and the late 80's TPI is supposed to be good almost to that range (5800-6000) So If I am smart with my cam, and chip programming I can build a 350 that pulls hard close to 6000RPM, well hopefully at least.

As for the injectors, yes If my intake has 350 injectors then I'd keep them, unless going with nitrous then I would probably replace with larger injectors and an upgraded fuel pump system.

Since I would like a 150 Shot of nitrous I do plan on using forged pistons, rods and crank. I'd love to find a 4 bolt main block that will work well with my 700R4. I might not know the complete compatibility chart of Chevy 350's, but I have built my fair share of engines, and I do KNOW nitrous makes weak engines go BOOM*. I also know that Mopar V-8 Distributors suck ***. But that is for a different message board. :-)

*(Actually it's more of a metallic clank or a thud sound although I bet nitrous could cause an engine to make a boom type sound.... not sure though.... never have put nitrous on any engine I've built)

I'm not really wanting to put out more than about 400 HP w/o N02. I'm betting that the factory intake will limit me on that, so realistically if I can get the magic 1 hp / CI then I'll be happy as with the juice I'd be close to 500 which is the practical limit for an F-Body drivetrain without major modifications.

I do plan on having the trans and rear end beefed up a bit as well, at least if I go ahead with the 150HP Nitrous shot and slicks for 1/4 Mile racing at the track. Nitrous and Slicks always find the weak spot in the drivetrain and break it.

I need to find a dyno and see what this car puts out so I have some basis of comparison. I know that the current engine cannot possibly be 100% stock parts as headers and 3" exhaust on a 305 does not make a 305 run like this one does. I just want to have a 350 in the car like it is supposed to have. So my hopes are to have a 350 which puts out more power than the 305 I have in it now.

Subframe connectors and strut tower brace are due in early next week. Hopefully I can get them installed before the holiday weekend.


P.S Sorry for the previous engrish subject line. I've since edited it.