Thread: rebuilding a 350 that has 305 heads

Tweet

I have a 72 chevelle that I've owned for about a year. It has a 350 block (#14016379) with 305 heads (#14014416) in it. It also came with an Edelbrock Performer intake, Edelbrock Q-Jet (1901) carb, and a Mallory Unilite electronic ignition system. I don't know anything else about the internals of the engine. It runs fine but burns oil and smokes when I start it up or gun it. I am not really satisfied with the power that it makes either. I have a buddy that is going to help me pull the engine and rebuild it. I am trying to decide what I want to do with it. Should I keep the same set up, get better heads and cam, or should I get it machined for a 383 stroker kit? I want to drive it daily on pump gas and still make close to 400 hp if possible. Oh yeah, I want to stay under $2000 for the budget too.

Do you want to stay with the stock converter or are you willing to step up to a looser one? What rearend gear ratio are you using?

The best way to make more hp on a daily driver is with more cubic inches. A very mild 454 will make 400-450 hp. A very slightly rough idling 383 with the right heads and intake will make 400 hp. A rough running moderatly rough running 350 will make 400 hp, but will require lower gears and a slippery torque converter. You could probably make 400 hp on the 383 with a stock converter which will help your milage and make the car more pleasant to drive in stop and go. Use GM's Vortec heads or something similar from the aftermarket.

I would rebuild it and keep it a 350. 2000 dollar budget isn't big enough for a stroker. Put some GM Vortec heads on and a nice street cam. You seem to have the carb and manifold covered with a aftermarket so that is no problem. Good ignition system already so your good on that.
Tech if he has a 72 and it's never been changed then I wouldn't doubt most likely he has freeway gears like 2.73's. Then again it could be anything but that is what I noticed in a lot of 73's and 84's and my 85 has them as well.

I just built a very nice daily driver 350. It gets my truck with 3.07 gears moving very quickly and the 50-70 acceleration is really fast. I built it with 9.25:1 compression using Keith Black 193 pistons, new Vortec heads, .010 off the deck, .020 out of the bore, summit stage 1 bushed rods, Comp XE256H cam, Edelbrock Performer Vortec intake, etc... The total came to $2600 for parts and labor. If you reuse your old block and rods, you can knock about $600 off that figure.

While I agree that a big block is the cheapest and easiest way to do it, the problem in the last few years has been in finding a rebuildable big block. richmondb, look through the little pennysaver / green sheet types of newspapers that you normally find on the corner at the 7-eleven. Many times, you can locate a 70's car or truck that has a big block in it that is not running and you can buy the whole vehicle for cheap. Lots of early to mid-70's Chevy station wagons had 402 big blocks in them and I'll bet you could find one of these cars for a song if you just look around. Scout around in the back alleys of Jacksonville, I'll bet there are quite a few candidates that you could have for just towing them off.

My car has the stock TH350 tranny and converter with the standard 10 bolt open differential, (not sure about the gears). I have been looking for a big block but the cost would be more than I can afford right now with having to get different a/c brackets, power steering brackets, a radiator, and everything else involved. That plus the gas mileage would kill me. I drive a lot of highway miles to work and move halfway across the country every 3 years (I'm active duty Navy). I have been leaning towards the 383 option. On www.enginekits.com I can pick up a balanced 383 stroker kit for $688. In addition to that, I would need to get the block machined, get new heads, and probably change the cam and I would be all set. Am I missing anything? I talked to a buddy who said I could probably get the machine work done for around $250. Does that sound about right? What heads and cam should I use if I go this route?

that's the whole point of finding a complete car, station wagon or truck with big block. You'd have everything there including core support, radiator, shroud, brackets, fan, viscous drive, etc., etc. If you think you're gonna be ahead of the game as far as gas mileage, you might want to think again. To make "x" power, it's gonna take the same amount of gas, whether you're running it through a small block or a big block. A big block just doesn't have to work as hard to do it and you don't have to spend as much money to get there as you would on a small block. Do a stock rebuild on a 402 with a slightly bigger cam and a 2,500 stall converter and it'll bolt right up to your TH350. Summit sells a Hughes converter for $159.95 that would work great with a mild cam and your stock rear gear.

I've been looking on ebay for a big block and didn't think about looking in the penny papers. I think I will run out and get one to check it out. It would be nice to be able to pick up the whole package and do a standard rebuild for less than it would cost me to build up my small block to make the same power.

Well, I looked in all of the trader papers and there aren't any older vehicles with big blocks to be found in the area. I even called a few salvage yards to see if they had any junk cars with big blocks in them. It seems like all of the big blocks get scooped up by the hot rod shops who sell them for an arm and a leg. I could probably get one rebuilt from one of those places for around $2,000 but after that I would still need all of the big block brackets and accessaries to go with it, which would cost too much money. I guess I really don't need 400 hp if that is the cheapest way to get it. I just want a setup that will give me enough power to have some fun once in a while on the street. I plan on keeping this car forever. Maybe eventually after I have enough time and money I can drop a big block in it, but for now I just need to get the engine in it running good and have some decent power to go along with it. Has anyone had any experience with the powerhouse 383 stroker kits on enginekits.com?

Ok here is what I think you should do. There is a book called Big Inch Chevy Small Blocks. Check that out and go from there. I have the one for Ford motors (when I was thinking of doing a 347 stroker for my 302) and they list a TON of different places to order full stroker kits from and say which are good and which are not. They will list some that are good for just fully aspirated or the ones that are good for just nitrous or nitrous AND super charged, etc. It is a good book and will help you save time, money and mistakes.

The kit on enginekits.com was used in Popular Hotrodding magazine and they had nothing but good things to say about it. What I am trying to figure out now is what heads and cam to buy. Does anybody have any advice on heads and a cam for a pump gas daily driver that has some power?

I like the stroker idea,but unless those 305 heads have been worked,get rid of them. They had tiny valves,and with 55 cc chambers would almost certainly cause tons of pre-ignition without running race gas.

You didn't say if you already have headers and a good exhaust system, if not you'll need them. You could just freshen the short block, add a kit to the tranny to help out there,and add edelbrock heads and their cam kit. Stay small on the headers,make sure you add a balance tube,it helps bottom end.I personally built a 350 bored .030 with 9.0 flat tops and a Crane dual pattern cam for my nova,added ported 883 heads and the result was to smoke tires at will and 22mpg driving with some intelligence. Hope that answers your question

I have dual 2 1/4 inch exhaust with 40 series flowmasters and stock exhaust manifolds. I will be getting aftermarket headers also. Which head and cam kit were you refering to?