I blew a piston in the 305 on my '87 IROC and figured since I decided on getting a different engine, I might as well upgrade to a 350. It's a manual transmission, and I understand these didn't originally come with a 350 engine. I need to know which of the three mentioned is the best option mainly in terms of total cost (cheapest) and the amount of work/modifications that will need to be done (simplest), maybe a brief list of what they will be, like wiring, fuel pressure, transmission, etc. Speed/hp isn't a top priority at this moment, I'll focus on that later on. Thanks in advance!

Also I got this car a year ago and am still learning mechanics so I can't answer much when people ask about current specs like torque, chassis, cam and crank, or even transmission. Where could I go to find someone who'd be able to identify these specs?

 

The L98 will be the cheapest and most straight forward of the 3.

 

The L98 would be the cheapest, most bolt in way to go. If it is a TPI car you will need to change injectors and PROM. Also, GM states that the T5 cannot handle the power of a 350.

 

T5 would be the transmission right? If that's the case, should I swap for a 90-91 Corvette ZR-1 transmission?

Other than that that's really all I needed to know, thanks guys

 

T-56 Swap would be MUCH easier, and probably cheaper than the ZF 6 speed.

 

Would AutoZone or O'Reilly be a reliable option to get the engine? I know they're refurbished and have 3 yr. warranty

Or even this engine? http://www.summitracing.com/parts/na...7353/overview/

http://www.jegs.com/i/GM+Performance...FdcegQodxdcKsQ

Both links are the same engine, but thought one might be further detailed than the other.
My only other alternative is http://www.hawksthirdgenparts.com/ca...ing-accessory/

 

From all of the research I have done on engine swaps for these cars that engine won't work without modifications. The TPI intake won't go onto those heads and you need a 1-piece rear main seal engine. As far as I know there isn't a single crate motor out there on the market that has heads that will work with the TPI intake.

So as far as I know, you have to buy a 350 short block and then buy a different seat of heads that will match up with the TPI intake.

 

So basically go with either AutoZone/O'Reilly (1-piece rear main seal engines) or used 100k miles engine from hawksthirdgenparts.com and get different heads, roger dodger.

Regarding the transmission, will the T5 no $#!t seriously be destroyed by the 350 or can it handle it if I just drive the IROC like a minivan? (Bear in mind that the L98 I'll be swapping won't have any modifications or upgrades). This is because my budget is tight and I can't upgrade to the T56 right away, most likely in a month or two after the engine.

 

You want a factory one piece rear main seal roller cam 350 motor from GM.That's the best way to go.

 

Don't let the "T5s will blow up the second you step on the gas of a 350! IT'LL IMPLODE" scare you. It's true a T5 can be blown to smithereens. It's true a 700R4 can be blown by the same 350. I've ran the same WCT5 for 13 years behind a 350 and it it's been fine. It's handled a few burnouts, quarter miles etc. Currently that engine lays 350ft lb to the wheels. A set of slicks or a few bad shifts could end the T5's life though.


I won't tell you not to swap in a T56 (they're great) but the T5 will live if you treat it nicely.

 

The easiest swap will likely be a Vortec 5.7L truck engine with a vortec pattern TPI base.

Bolt everything else you have back up to it, and run your dizzy. Then run either a L98 stock chip, or have a mail-order done if you aren't interested in getting into tuning.

The stock Vortec L31 cam is smaller than the L98 but its basically the same as the B-body Iron headed LT-1 cam (big surprise considering they are basically the same engine). That tiny cam and bolt-ons was enough to send my GTA @ 3750lbs race weight to a 13.3 @ 103mph. The car felt great, got great fuel economy with the 6spd too, I averaged 30-32mpg highway and around 22-24mpg around town.

Add in a regular LT1 F-body cam, or L98 cam and it will run very well with plenty of power an torque and sacrifice no street manners compared to a bone stock car.

As long as you keep the stock L31 cam, or go with a factory L98/LT1 cam you could probably run without any tuning whatsoever.

 

If that was true then my 10-bolt rear end would have exploded the minute I stomped on it or power shifted my AFR195 headed LT1. Though, I'm not sure it likes the power shifts at 6800rpm.