rebuilding a 350 that has 305 heads

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?

Vortec heads from a 350 will work fine. There are some aftermarket companies out there selling them. I even think Jeg's does too. I wish I could find a Ford stroker kit for as cheap as the 383 stroker kit you found. That is what I hate about trying to fix up my 302 is everything is way more than a Chevy.

I would like to get Vortec heads but then I would need to get a different intake wouldn't I? What about cam selection?

I thought the Edelbrock Performer Series intake manifold worked with Vortec heads? I mean, I am not saying it does but that is what I thought. Am I wrong?

GM Performance Parts and Edelbrock both make intake manifolds for Vortec heads. They start at about $150 from Summit.

There is an Edelbrock Performer that fits the Vortec Heads but I don't think mine is the one since it is attached to regular heads right now. I'll price out the Vortec heads with the new intake and cam to see if I can fit it into my budget.

Yeah if that is what you really want and I think would be worth it then you can always sell the intake you have now or keep and save it for another project for later. Those 305 heads are really constricting power. They are basically junk, especially with no work done on them.

Okay guys, here is what I am planning on doing. If the 350 does not need machine work than I am planning on buying the Sealed Power engine rebuild kit from Summit that makes 9.35:1 cr with 64cc heads. It goes for $219.95. I am also planning on buying the stock GM Vortec head kit with a performer intake from SPDC that costs $729.95. The only thing I have left to buy is the cam. What cam do you guys recommend? The stock vortec head kit says it is compatible with valve lift of up to 0.450". Should I go with the upgraded kit that is good for .550" lift?

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Originally posted by richmondb
Okay guys, here is what I am planning on doing. If the 350 does not need machine work than I am planning on buying the Sealed Power engine rebuild kit from Summit that makes 9.35:1 cr with 64cc heads. It goes for $219.95. I am also planning on buying the stock GM Vortec head kit with a performer intake from SPDC that costs $729.95. The only thing I have left to buy is the cam. What cam do you guys recommend? The stock vortec head kit says it is compatible with valve lift of up to 0.450". Should I go with the upgraded kit that is good for .550" lift?

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The G.M. Vortec heads are fine.But here is another idea.How about a Dart Iron Eagle SS head.1.94.1.50 stainless steel valves,165 cc intake ports,screw in studs,.Competion Products sells these for $ 560 plus shipping.If it where up to me I would buy these over the Vortec heads just based on the fact that they are a much heavier casting and less prone to cracking and wrapping.

Someone beat me to the small valves and chambers comment. You want some heads with the mighty 202s. Smoking at start up is a good indication that the valve guides in those heads are shot anyway. If you have a 2K budged, I'd spend half of it on heads. Get some good aluminum heads, and you're on the right track.

AS for the big block / small block vs. gas milage theory: The best way to get more power from an engine is to improve its EFFICIENCY. When you step up the compression, larger cam, headers, port n' polish, multi-angle valve grind, etc... you are improving the engine efficiency. Until you go to extremes.. and if you are doing a daily driver, then you don't want extremes. Extreme cams wear down, stiff springs stretch the timing chain, etc. If the price of gas is an issue, then build the 350 for 300-350 HP. You don't want a toy you can't afford to play with.

I gotta agree with halftanked on getting rid of those 305 heads. Had the same basic setup in my '70 Elky and it pinged like crazy once it got hot unless I ran the timing a bit retarded which didn't do anything but kill the performance.

Hey richmondb, I got the balanced kit from powerhouse and it was not to good. I got the one piece rear main seal crank for a 94 block. The first thing I had to do is when I put the crank in, it was hitting the block right where the oil dipstick went in on the oil pan gasket boss. Not a problem to fix with a die grinder and about 1 min. of grinding, other than that every thing else cleared except the piston skirts hit on the counterbalance on about 5 of the pistons. I got that problem taken care of and busted #5 piston. I called and ordered a new set of pistons and when I got them, one already had a hole in it. They shipped me another one but still took a week to get it. Their parts are ok but check everything very well before you put anything in the block. I still run the rods and crank but I went with Speed Pro pistons this time. I think their pistons are pretty much junk and may be seconds or something. I do know one thing, the crank fits in the block without much machine work. As far as power and torque, them strokers sure has got it going on.

Kodiak

So what have you done about the 302 head problem? Get rid of them and find some other GOOD heads?

Here's my plan, because i'm sorta in the same situation as you are. I had a good starting point but until the other day, no direction. But now I think I've decided what i'm looking for.

I'm going to build my 350 so that it gets 1hp = 1cui or at least get it as close as possible. I'll build it so that it is a good, stout running engine. Then spray it. This way, at 350 hp, i'll be able to afford to go and cruise or what not, then when i'm at the track and i need that extra oomph that i'd have gotten from that 400-500 hp motor I can have it. Don't take my advice without some other research and what not first though. Nitrous can be the best choice you've ever made, or it can be the reason that your car is in ashes. It's all about how you deal with it and what precautions you take. A good strong 350 or 383 with a set of good flowing heads and about 50-100 shot of nitrous would get you close to where u want to be without breaking your wallet everytime you go to fill up your gas tank. JMO, and i really hope that i get some feedback on this opinion here because I can't seem to find anyone on here to comment on nitrous use as far as what's safe for a stock block, stock rods and pistons and the different types of upgraded parts.