I have an '89 RS with 305 TBI, and was wondering what I should look out for when swaping in a 350 Carb 4 bolt Main out of a '79 Chevy Pickup. The motor runs good, doesn't smoke or anything. I want to tear it down and rebuild to get about 300 Horses. So,......whats it gonna take. This is gonna by a first for me. I will still be using the stock 700-R4 tranny.

 

Well, probably 300 horses and the stock 700r4 isnt a very good idea. I wouldnt expect it to last long, anyway. As far as the 350, you basically need to ditch everything down to the short block. The distributor is OK, with a little work. If it has a 4 barrel intake, you could reuse it. With how cheap aluminum intakes are nowadays, it seems silly though.

 

You should double-check the dip stick set-up. Many truck engines (including our '74 4-Bolt 350 Block) have the stick on the Driver's Side. Not a problem if you're using headers..

Sincerely,
Kurt

 

Yeah i want to go through the engine and take it to a machine shop and bore it .30 over, would I need bigger pistons or just different rings. I'm also confused about crank size. If I bore it out and use stock heads Do I need a larger crank? I want the heads ported and polished at the shop also.

One more question, how much of a pain is it to loose the tbi and computer set up. I want a carb.

 

Easy. The only thing you have to think about is the power for the distributor and any wiring for guages you want to keep alive. I had my carbed engine up and running in a weekend.

I'd recommend NOT tearing out the EFI stuff though. You may want to go back to it someday. I am still using a carb on my setup but decided to let the ECM still control the tranny lockup. So it is still fully functional except it has no control of spark or injectors.

 

Yes. But.... Why punch it .30 over UNLESS it's needed? Have the machine shop check the current Bores and Pistons.... IMPO Don't punch it unless the bores require it. Sometimes a good hone and a New set of rings is all that is needed and a Punch to .30 is nothing more than a complete waste of $$. Spend your money on something that will make better use of the funds.

NO.

Do you have emissions requirements? If so, it's definately NOT a good idea at all. I personally prefer CCC-Carb over the TBI... But I also prefer TPI over CCC-Carb. IMPO - TPI is the best!

Question?
Have you considered a Long-Block from one of the big name outfits? You can get a BRAND-NEW 350 block for about $1500 (including shipping) from Scroggin-Dickey for less than SOME machine shops are going to charge for the services you have outlined (it won't have ported or polished heads).

My
Kurt

 

Don't bother with that operation on truck heads.

 

IIRC, the 70's heads are larger chamber, lower compression - this will provide less power than a smaller chamber head. I bought a 350 used - the builder used 70's heads, but added 10:1 dometop pistons to reduce the chamber and increase the compression a bit to help compensate. If your going into the block anyways, you might consider this as an option (although it does mean cash spent on new pistons). If you use dometop pistons, you'll have to get shorty plugs (plugs with less threads - ie don't go into the chamber as deeply), as the pistons will hit the plugs (mine did).

Like was said, porting those heads a waste of cash/time.

Also like was said, keep the TBI stuff in there, at least to start with. Although I disconnected all the stuff, it's all still there, tucked away neatly. You can ditch the ECM and all ECM control over everything and go carb (if the Smog **** allows in your area), but you'll need an HEI dizzy (brand new brown-cap Accel at Autozone for $125) and a method of locking up the torque converter (vacuum-controls available from B&M and TCI +/- $90), and you'll need the Mallory 3-port fuel presure reg ($90) to reduce the pressure for the carb. All the tuning pros use Holley carbs, Edelbrock is for us dummies - I used the EDL-1406 ($269 at Pep Boys brand new) - it runs right out of the box with very little adjusting.

That's about it. Don't be surprised if the tranny goes south after completion, mine was obviously slipping before my swap, but the 305 didn't have the oommmpppphhh (a technical term) to let the slip be felt, 'cause now you can really tell the slip behind the grunt of the 350 - I'm on the hunt for another 700R4. I think the 700R4 will handle a mild 350 OK, as long as it's not a really built-up HP monster 350. And a pretty basic 350 and mild cam will really feel nice after the 305 - I'm really loving mine ( except when my foot is heavy and the tranny slips).

I'm no expert, and I didn't go for 10,000 HP, but I recently did mine on the cheap just to get a decent street ride, and I'm loving the results - feel free to email me anytime with questions and I'll tell ya what I can.

 

My 305 700R4 held up just fine behind my new 350 (supposedly around 350hp). As far as I know they are the same thing found behind a Z28.

 

The stock '79 350 longblock can easily make 300 horses if its in good shape, even with the crappy heads. Its not hard or expensive to do. I had a stock '79 Z28 350 in my car last spring (same as your truck 350 almost exactly).

What I did was to change out the intake manifold for an aftermarket Edelbrock one (I used a Torker, but you'd be better off with something else, trust me), I used a stock vacuum advace HEI with a hotter coil, and install a set of headers and a good exhaust system. Judging by the MPH my car ran at the track it made about 270 fwhp. If you just used a better intake manifold than I used, like a Perf RPM, then you'd be right near your 300hp goal.

 

Its not that they are any different, its just the fact that stock, they are relatively weak anyway. When one has lots of miles on it, its only worse.