angel2794

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?

RyanJB

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

Veaceonee

iTrader: (1)

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.

angel2794

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

Veaceonee

iTrader: (1)

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

angel2794

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/

Dartht33bagger

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.

angel2794

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.

Steve Mack

iTrader: (5)

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

aliceempire

iTrader: (14)

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.

Thirdgen89GTA

iTrader: (5)

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.

Thirdgen89GTA

iTrader: (5)

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.