MR-IROC-Z

hey guys I have a 90 iroc Ihave the original 305
In it it runs fine just want a 350in it what will Ineed to have it running just the way
It should??new ecm?can i use vortec heads ? I was think of a 350 vortec block
Any help Iwill apreciate it a lot thanks

rusty vango

its easy ,you don't need a lot of expensive things. BUT do a search, because this swap has been done to death.

Miguel661

I'm looking to do the same thing, so my question is where should I get my engine from?

rusty vango

about any junk yard worth its salt will have a selection of them. my suggestion would be look for one made between 87 and 92. I might add that you may not want a "vortec" as they are different from the gen 1 sbc. mainly the intakes are different and not cheap.

Miguel661

Rusty thanks man I'll look for one in the junk yard, I just wasn't sure if I should buy a crate or get a used one from a truck but thanks for the info.

Nighthawkf-117

iTrader: (1)

I am doing a vortec block 350 swap next summer. The reason i decided to go with a vortec block is the design refinements of the block. Gaskets have been optimized and these engines rarely leak. Additionally because of the EFI system used on these engines they rarely need to be machined. Many people hand hone and scrape the gasket surfaces, then simply rebuild with original components with new rings and bearings. Just something to think about.

Bigfoottpi11

You just need 350 Knock sensor, injectors and chip

90IrocConvert

I just finished a swap on my 90 Iroc. I put a 89 corvette TPI and used the plenum off my 305 and changed the knock sensor to a 5.7 for a 90. I took all my sensors off the 305 and put them on the 350. The car starts but comes to a quick stop. Then is rough to turn over. I have tried several different things but still end up with the same result. I have a feeling it may have something to do with the oil sending unit or somewhere along that field. Does anyone have suggestions? The sending unit happens to be located on the intake manifold on the corvette engine but mine was located above the oil filter. Does it make a difference?

91TransAmVert

i'm looking to do a 350 swap into my 91 305tpi TA cause it has 205k on it, already decided to get a junkyard block, but honestly the most difficulty i have found is what vehicles to get it from someone said like 87 - 92 or such but what models should i look in and at? I can get a bare block from my upullit for like 25-50 dollars. Really i need any swap 318 or 350. My upullit doesnt come up with sport cars very often so it would have to be a truck, van, suv etc..

drdave88

iTrader: (3)

Something to consider when getting an engine is what its coming out of. You are going to want to see what heads/cam its currently got in it. A truck or van wont have nearly the same type of heads/cam that an F-body or similar would have. Find one you are interested in, check the casting number on the block and heads to get an idea of what it is and make a decision from there.

91TransAmVert

I just need a bare block, I plan on getting all new heads and cam.

Night rider327

iTrader: (13)

As far as the blocks go, any 1968/69 327 lg journal, or 1969-2002 350 gen 1 block will work fine.

Only a few changes to the blocks through out the years. Biggest thing is the flat tappet/roller cam change and the 2 pc./1 pc rear main seal change

1987 was the start of the 1 pc rear seal, pass. side dipstick and roller cams (roller cam blocks only in performance cars)

The trucks, vans, SUVs didn't get the roller cam blocks untill 1996 with the start of the vortec 350 engine.

The 350 was used in just about every mid and full size car chevy made, along with all the full size chevy/gmc trucks/vans/suv's. The 350 was std. in some cars and options in others so before to have a casting number and suffix code guide handy when looking in the car bone yards for a 350 block.

rusty vango

I have found ,from 87 on ALL blocks were cast with the roller cam provisions.that does not mean all engines got a roller cam ,however. some are drilled and tapped for the "spider" bolts and cam retainer. some are not.

90IrocConvert

I actually found out what the issue was that was holdings from completing my 90 iroc 305TPI to an L98TPI. The motor would start but then stop after a couple seconds. What the issue was after process of elimination, was a rubber O ring in the fuel rail was slightly cracked. Possibly from drying out. I found this out by finally hooking up a fuel pressure tester and found that the pressure drastically dropped. I pinched the return line, no change. Then supply line after prime, no change. Finally both then I could hear the air escaping. I just thought I would share invade anyone else runs into an issue similar.