KustomIroc

Hi Guys, well the Iroc is away for another winter. I have 168,000 kms on my 86 305 TPI motor and I was wondering should I rebuild it or replace it? I was thinking of 3 other things.......a 350 crate motor? A 383 stroker
that I can build or a ZZ4. Can a ZZ4 be a direct replacement? How hard would it be to put this motor in my Iroc and still use the TPI? I have a friend that put Z502 in his but he went to carburated. Please post any thing you want to say or mention or any suggestions.

Thanks,
Jamie

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Jamie James
1986 Iroc-Z 305 TPI
1.90 60 ft 14.15@ 95.75
1.74 60 ft 12.84@107.75 on the bottle.
My IROC:
http://personal.nbnet.nb.ca/jjames/homepage.htm

86_327_camaro

i would say to make it a lot easier go with a carb and a vacuum advance distributor

five7kid

iTrader: (14)

Easier? Let's compare.

Crate engine w/TPI:
Pull 305, set beside crate engine, swap things from the 305 that aren't on the crate engine, put new engine in, start it up.

Crate engine w/carb:
Pull 305, set beside crate engine. Transfer engine mounts. Go to parts store, get intake manifold and gaskets, install on crate engine. Install engine. Go to parts store or junk yard, get vacuum/mechanical distributor, install on engine. Go back to above, get carb, install on engine. Try to install alternator/AC, discover brackets won't mount to carb intake, back to junkyard. See bunch of wires no longer needed, decide to cut them off. Pull out computer for good measure. Try to hook up alternator, distributor and choke, get out wiring diagram and trace them out of the harness connector just cut, splice back in cut wires. Go to hook up throttle and TV cable, humm, wrong length, no place to mount - back to junkyard. Carb needs fuel, back to parts store for 3/8" rubber and steel lines, clamps, and tool to bend. Okay, ready to fire up, turn key, turns over but no fire. Oh, in-tank fuel pump not running. Rewire after studying wiring diagram for a couple of more hours. Try to start again, carb floods horribly, almost start car and garage on fire - Back to parts store for a 3-port fuel pressure regulator and more fuel line stuff. Oops, no air cleaner, back to parts store/junkyard. Finally get it on the road, discover SES light always on and TCC doesn't lock up. Order lockup kit from Summit, while waiting for it to arrive pull out instrument cluster and pull bulb out of SES (actually take cluster out twice because got the wrong bulb 1st time). Mileage down, cold starting harder, fiddle with carb for two weeks getting it tuned so throttle response acceptable. Go to renew registration 8 months later, need emissions test first. Exactly what you trying to pull here, put the factory computer controlled equipment back on...

Okay, I over-simplified the TPI part. The ZZ4 has Vette aluminum heads w/o EGR and different angle center intake bolts than the '86. Need 1-piece rear main flex plate. The intake bolt angle/rear main seal type will have to be considered regardless of engine or induction used. Will need AFPR to get the 305 injectors to work w/350, or 22# injectors. With the carb swap, you can plan ahead and get what you need before you start, but I bet you'll be searching for something you forgot before it is back on the road. If you need emissions inspection, the carb swap you suggest is moot anyway.

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82 Berlinetta, orig V-6 car, now w/86 LG4/TH700R. 2.73 unlimited slip. Cat-back from '91 GTA, Accel HEI SuperCoil. AMSOIL syn lubes bumper-to-bumper. Daily driver, work-in-progress (LB9 w/ZZ3 cam, TBD heads, exhaust, paint, etc.).
57 Bel Air, my 1st car. 0.030 over 396, Weiand Action+, Edelbrock 1901 Q-Jet, Jacobs Omnipack, 1-3/4" headers, TH400 w/TCI Sat Night Special conv & shift kit, 3.08 10-bolt, AMSOIL syn lubes bumper-to-bumper. Best 15.1 @ 5800' Bandimere. Daily driver while Camaro was being put together.

86_327_camaro

sorry for suggesting something. i was unaware that everyone worships the black box under the dash. personally i think its extra weight

KustomIroc

Thanks guys I appreciate everyone's opinion, however, I am planning to keep the TPI setup with whatever I decide.

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Jamie James
1986 Iroc-Z 305 TPI
1.90 60 ft 14.15@ 95.75
1.74 60 ft 12.84@107.75 on the bottle.
My IROC:
http://personal.nbnet.nb.ca/jjames/homepage.htm

five7kid

iTrader: (14)

You should port your plenum and improve exhaust flow, preferably with headers and high flow y-pipe, cat, & cat-back. This is true with the 305 or any engine you indicated you are considering. Be careful to avoid any engine with Vortec or Fastburn heads, as your TPI manifold will not match it correctly.

At the risk of going on too much, there is a big difference between "worshipping" and "appreciating" black boxes. I'm a mechanical engineer working on rockets originally designed in the 50's & 60's, currently used to launch satellites. The mechanical systems back then were largely open-loop or mechanical feedback. Over the years, they have been replaced by closed-loop, software-controlled systems. Why? Better response in use, better ability to taylor use, better overall performance, reduced costs, and reduced weight. Although Kustom has already stated he's planning on keeping the TPI, in general, people all too quickly abandon 80's and 90's technology (updateable in our new century) for 50's and 60's systems. That doesn't make sense to me for performance, cost, or operability. Cost is arguably higher now, but not if all performance factors are considered. Originally I challenged your "easier" statement, which I maintain it is not, but you expanded it well beyond that with your next statement.

Of course, there are still people that insist there is no difference between petroleum and synthetic oil. I don't see many people driving around on bias ply tires, though. How long it takes each individual to get comfortable with current technology is a personal matter, I suppose.

Okay, it's somebody else's soapbox now...

86_327_camaro

well to tell the truth i'm a mechanical engineering student in my 3rd year. and as I originally understood it fuel injection and computer controlled vehicles were not better from a performance standpoint. Fuel injection and computer controls were started because of the government and the little thing called emissions. it is a lot easier to get a couple of million cars calibrated for emissions by fuel injection. but as far as horsepower, slap on a 4 barrell

TexasLT1

that was then, this is now. I would say absolutely stick with TPI, or, how about LT1?

Dave86IROC

From experience I would recommend a 406 smallblock with a SuperRam/Mini-Ram EFI setup. I converted my 86 over to 4bbl and I regret it. In the end it probably didn't cost much less and was a big headache and in the end the fuel economy would have probably made it more expensive. When I do it again i'll stay EFI all the way. For a performance motor though, you really need an aftermarket tuned port setup because the factory one really can't cut it (even modified). Good luck with whatever you decide...