I am not real pleased with my "rescue" motor's performance. Its smooth and runs well, but uninspiring. Granted I have poor gears, the tube exahust manifolds and no idea what cam the PO had in it, so not fault of the engine, but I want more.

So, I guess where is the bang for the buck? Should I go out and get some 5A heads to replace my 3A heads?

I KNOW I want to get the better flowing exhaust manifolds (I'm not ready for headers) and I'd like suggestions in regards to cam considering the following:

3A heads or 5A heads, exhaust manifolds off a 73 Cutlass, 2200 stall convertor with 3.23 or 3.42 gears in the rear. According to the calculators 3A heads are ~8:1 compression and 5As would be a tad over 9:1.

The car will be used as a daily driver and run down at the track in the summer time just for kicks.

thanks.

sb

 

Start with the gears and go from there. Those will by far be the best bang for the buck.
I had an 80 (A body BTW) that started life with a 260. That lasted all of 2 weeks when I dropped in the 350 I had waiting in the wings from a wreck that happened to me.
After blowing the rear end in various ways 3 times (2.28 gears all off them) I finally was GIVEN a 3.23 posi gear set out of a Camaro and the guy installed it for me for free as well. WOW what a difference.

 

I have almost the same story.
Went to a 3.23 from the fact 2.29, on a 260 powered 79, and YEOWWWWW!
Like Scotty found warp drive!
A blown 502 will feel tired with that 2.29 gearing, your 350 would fare no better.
Gears are the absolute #1 first thing you should do, before even changing oil, or plug wires.
A set of #5 (with no bloody A), 6,7or 7a would be next on my list.
Jim

 

LOL! I have given the same advice for gears many times myself! I am going out to get gears today. I have been looking for them for some time. Do I pull the heads off a 307 today or not?

I would love to find #5 or 6 heads, but the odds are slim. I can get the 307 heads cheap and readily available. Are the 5A heads a step in the wrong direction?

Any cam reccomendations?

sb

 

Big step backwards.
Where are you located?
Jim

 

I am in San Antonio, TX.

I was hoping the smaller combustion chamber would help with compression. But if they are not the answer, then I will keep looking for 5s or 6s or 7s. I am on my way to go get some 3.42s right now.

So, with my ~8.0 compression ratio, any tips for a cam?

sb

 

SB heads are not hard to find at all. Core sets are usually $100 or less. If you are looking for earlier 330 castings like #4's, those might be a little harder to get your hands on. When you say 5A heads you need to be more specific & use casting #s. Olds had 5A's in 1969 that had 68cc chambers & they also used them on the 307s from 1980 thru 1985. The latter had smaller ports for better fuel economy. They were not good for performance. It's my opinion after you change the gear you should concentrate your efforts on bumping up the compression & getting a top end matched component set - cam, intake, carb & headers, if you want to reach the potential of your Olds.

 

They may cost a little more upfront but I'd bet you could find at least half a dozen guys on this site with extra early small block heads. I have several extra sets myself out in Oregon. When your ready create a parts wanted post, and include your location. If your lucky, you might find someone within driving distance who has them. John

 

7a heads are from 1972 and have hardened valve seats for sure. I think 7 heads from 1971 also have them but not 100% sure. If you only plan on a valve job, there are the one I would go with. There are lots of them around but you need to find some as close as possible because shipping is expensive.

 

Picked up some 3.42 gears and carrier with new bearings, pinion seal and crush sleeve for $100.

First step in curing anemia.

sb

 

Glad to hear that you are getting some gears.
Do some tuning once they are installed (timing, curve, vac/mech advance, jetting etc.).

Since you are currently running 3A heads, that means you have a later block with 1/2 inch head bolts. All earlier heads use a 7/16 head bolt, and the head bolt holes in the head must be drilled out with a 17/32 drill bit.

I have some 7a heads for sale here locally for $150. I'd rather not ship, unless I could find someone willing to give them a ride.
These had a valve job done years ago, they would still need to be drilled out.
Jim

 

Actually, the block is a 71...it is a rescue. When I picked it up the thrust bearing was HAMMERED into the #1 main saddle. I got it all sorted out. I should have done more research with the cam and heads, but didn't and now I am sorry. I picked the 3A heads up from a friend at a machine shop for $100. Completely re-done and ready to run. The block had some 2A heads with it and I was at least smart enough not to run those.

So, all that to say I am using 7/16 head bolts from who knows what (one of my mopars I think) that are long enough to accomodate a washer. So, when and if I find more favorable heads, I will not have to do any drilling.

sb

 

Not finding anything that old in the local JYs. I found one 403, but those heads have HUGE combustion chambers. (4As)

I will keep looking.

Warhead: no worries on those heads. (Unless you do find someone coming this way) I'll work with these for the time being with these new gears and better exhaust. Then about a week later I'll want some more.

sb

 

I found someone who will be coming that way in about a month.
He will be driving through San Antonio.
Send me a PM if you are interested in the heads, and some factory 7/16ths head bolts.
Jim

 

Well, I got the gears in (3.42s). Big difference, but the motor does still seem like not enough for what it is.....the quest continues.

sb

 

UPDATE: found water in the oil. Put the pressure tester on it, and it quickly built to 30 psi. I pulled the heads, but have not yet found an obvious problem with the head gasket nor any cracks that are readily visible.

In short, the engine is coming out to get magnafluxed and possibly x-rayed.

Yay!

sb