Hello all. Looking for some advice and this seems like the perfect place. I've got an '86 t/a with an LG4, 4bbl q-jet. Well, I'm looking to swap out the crap LG4 with a 350. I was originally going to build the 305, but that seems like a serious waste of time. For an extra what, $200, I can build a 350 instead of a 305. Nuff said. Only problem being I bought some crap already planning for the 305.

1) Which 350 block should I pickup? I'm not looking to spend a lot, junkyard 350 more than likely. Any 1986-1992 350 should be ok?

2) Is there any way to get decent performance out of the LG4 heads? Port and polishing them maybe? I already bought new valve springs:

http://store.summitracing.com/partde...EDL-5802&N=120 300527

Had the heads cleaned and reassembled.(free) Valves were fine. Am I going to be killing the 350 with these heads?

3) Any computer changes going to be necessary? It already has a Hypertech thermomaster chip(P/N:11612). Would I need to buy a chip for a 350 and swap it? I also know that none of the 350s were built with a 4bbl. All were TPI. Any problems there?

4) Ignition suggestions? I purchased a distributor tune-up kit, but it seems the ignition module won't fit the standard connectors in the distributor. Will this be sufficient, ya think, and what the hell do I need to make this ignition module work with the stock distributor?

http://store.summitracing.com/partde...-66945RC&N=120 305246

Picture of old, and new ignition module:

http://home.comcast.net/~kedzepe/IMAG0003.JPG

Got a shift kit for the 700r4 as well, pretty easy to install:

http://store.summitracing.com/partde...=TRG-700&N=120 301933

Headers:

http://store.summitracing.com/partde...=TRG-700&N=120 301933

Not the best, but remember I'm on a budget here. Purchased a larger trans pan with drain plug as well, and some roller tip rockers.

http://store.summitracing.com/partde...M-141507&N=120 301810

I also plan on getting a decent cam, timing chain, possibly a stall converter, and EVENTUALLY replacing the crap 2.73 rear end.

Anything else I should worry about? Suggestions?

 

yeah, allmost all chevy vans or a caprice.. my 350 came out of a van its now a 383 i bet they never intended for that to happen

and yes you're REALLY going to want to ditch thos heads....

 

Figured as much. Are there any issues with the computer controlled carb, or anything that needs to be changed computer wise when swapping the 350 in for a 305?

The stock heads should be ok until I can afford better, right? I mean, eventually I'll get some nice heads, but right now its not in the budget. Same heads came on the 305s as the 350s I thought.

How about that ignition module? lol Do I need to get a 7 pin module, or is there some kind of change I can make to make the 4 pin work?

Thanks for the reply.

 

If you do the standard do-it-yourself porting job, have 1.94" intake valves installed, pin the studs or have screw-in studs installed, and put in decent valve springs & seals, the stock 305 heads are more than adequate for a good street performance 350, and better than the typical factory 350 head for said performance.

The stock q-jet will be fine with basic tuning.

Sorry, you need the 7-pin.

 

Yeah, I'll have to keep bugging the hell out of Pro-Form, or just toss the $50 on the accel 7 pin module.

About the heads...sounds good. A buddy of mine did the porting jobs on his LT1 383 stroker himself, so we should be able to handle my cast iron heads. A lot slower, and harder to screw up than aluminum. lol

I've done the tweaks to the Q-jet mentioned here on the site a couple years ago, so I'll just need to tune it out once I drop the 350 in there. Any suggestions for a good cam?

These are the cams I was considering, since they are designed for the stock ECM.

http://store.summitracing.com/partde...12-388-4&N=120 4294925232 4294924497 304550

http://store.summitracing.com/partde...12-402-4&N=120 4294925232 4294924497 304550

Is the extra lift on the hydraulic roller tappet cams really worth double the price? Any other benefit to those cams? Easier to install, in that they don't require break in really?

 

If I had a roller block with lifters and pushrods in good shape, I'd prefer keeping it roller vs. conversion to flat tappet. The roller is a little better overall, but whether it's $150 better - that's really up to you.

 

Won't really know that until I pickup the 350. Probably hold off on the cam until I find the 350. Just trying to plan ahead as much as possible here. The pushrods and the lifters on the LG4 appear to be in perfect shape, so even if I pickup a 350 with shot lifters or pushrods, can the LG4 lifters and pushrods be used?? Probably not a good idea eh?

 

Is your LG4 a roller block? If not you'll have to toss those lifters anyway.

 

You can tell its Friday, I'm not thinking for crap. No, its not a roller block. So, yeah, stupid question I asked. heh

 

I also have an 86 with the 305 4bbl. It seems that 1986 was a transition year for engines. When looking up parts or even blocks, it is up to 1985 or from 1987? Whats up with that? I know it has something to do with a one piece rear seal or two piece. My question along the same lines is, what 350 should I get to build that will use most of my existing wiring, computer, ect...? I am going to stay with the carb, possibly upgrading to a holley and still be compatible with my 700r4. Any advise would be helpful.....

 

You can get any chevy 350 from 87 and up, because they didnt make any 350's from 82 to 86 thanks to the great emission laws back then.The 350 will be compatible with ur 700r4 with out a doubt, but u might have to change ur ECM. If i were u i would grab a pair of vortec heads from a junk yard or a new set from scoggin dickey for about $240.00 new, or a little more for a modified set.