need advice for 350 4 bolt main

first id like to say im happy to have found a performance forum like this.

i am not neccesarily a newb when it comes to putting engines together but i am when it comes to building a high performance engine. heres what im trying to do:

i have an 81 gmc shortbed stepside. switching out the factory 305 for a 350 4 bolt main bored 60 over. putting in a 500 lift cam with flat top pistons. going to purchase edelbrock performer rpm heads and manifold to use with 750 holley. using super competition hooker headers and gonna install a 700r4 level 2 tranny.

if this setup doesnt seem right or maybe i should go another route with some of the parts, please let me know. i am still in the process of building the bottom end so i can change most of this set up at this point. this truck will be a playtoy mostly but i may run it at the local strip every now and then(1/8th). any idea how much hp or torque this will be putting out?? any help and suggestions with this matter is greatly appreciated. :smoker2:

i just wanna make sure im getting the most out of this motor for the cash im putting into it

A good stall speed converter and flomaster exhaust :)

hmmmm well with that set up... you should be cranking an approximate 330-340Hp at the Crank. Torque... 360-380ish...

Is the engine a ZZ4 based engine? Stock they make 355hp 405ft-lbs of Tq.

If your looking for the best bang for your buck, go with a Vortec 350 straight from Gm. its a good solid 330hp and 380tq. You can also get the new Vortec heads that have better springs for better power.

if you're a tinker junky, plan on buying more than 1 carb and more than 1 intake if you want to find out what works best for your car..err truck.. certain size carbs give better low end torque... some manifolds give better high end pull its all up to you of course =).

the 700R4 tranny is a good unit, that Overdrive is a gas saver on long trips. It shouuldd hold up against the power of the engine, you shouldnt have tooo much problems until you reach the mid 400's in torque and Hp...


Overall, i think your set up should move that stepside right along.
Good Luck with da Trukk!

since your still building the bottom end... why not get a hold of a 383 kit, new crank, rods, and what not. theres a full-size GMC truck here where I live running low 12's on a 383 setup, 3-inch exhaust, and various other goodies. i got a friend with a 383 in an s10 with a t5 trans... he burns out through 3 gears, only runs a high 14 though, mainly because of traction problems.

a buddie of mine built a 450hp 350ci in a 84 S10. with a 200hp Shot of Nitrous.

It had a built transmission... a drive shaft that was like 4 inches in diameter, a beefy rear end... fuel cell... and it was lifted for offroad use.

what happend to it? blew up the tranny first time out.

parted out the truck for less than it was worth. (at least 14k in all the high performance goodies)

i never said i was friends with smart people. :rolleyes:

damn that sux, just read your sig, nice year model nova, always liked the 70's models...what do u run in the 1/4?

thanks for all the info guys. seems i have a lot of decision making and planning to do so i gonna take my time and not rush into anything. :D

mr higgs, i just read that you plan on putting a 750 holley on it. I wouldn't go that high. The number one mistake when it comes to carbs is over carbing a car. That 750 would go with a 454 or 500, for a 350 I wouldnt go any further than a 650. If you do decide to go with a 750 you will bog down a little to much. Just my 2 cents

i never bogged down with my 750 on my old 350. was a great daily driver for.. about a year. Never once bogged... except when it was mistuned and was running so rich it was like i was the one sole cause for LA's Smog problem.


Sorry LA... i fixed it.. didnt i? :licker:

sounds like you have a decent buildup goin on... with the intake, i'd go for the RPM Air-Gap. they flow really well in the high rpms, and don't sacrifice low end torque. as for the carb, i'd personally go for a Demon 750 rather than a Holley. just a personal preference. i'd estimate you HP to be around 350-375 depending on how big your combustion chambers are with those flatties, if you mill the heads, or deck the block. just be careful not to let your compression ratio go above 10.5:1 else you'll run into detonation problems.

Unless you want to do the work yourself check out www.badassracing.com They build custom engines that make some major hp(one of their bigest is a blown big block with 1500 hp). They have a couple of specials right now on some 4 bolt 350s so check it out.