330 heads on a 307 Olds small block

[KrisW]

I recently received a PM with concerns on this topic which has been discussed a long time ago on the forums. My response is below for the public to use as well or comment on:

"You should be able to get by with normal small block Olds pushrods for a non-roller cam. If you are going to an auto parts store, specify the pushrods to be for a 1975-80 350 Oldsmobile V8. they have large oiling holes and work fine for a stock type application.

You also need to be prepared to buy a new intake, unless you have the old 330 intake as well. The 330 heads are far superior to your 307 pieces, and the size of the intake ports is only one benefit. The 307 intake will bolt up, but the ports will be badly mis-aligned and you will have lots of problems when running. Buy an aftermarket intake, such as the performer rpm Olds small block intake, to get maximum benefit from your increased compression ratio and intake flow.

Also, now is the time to dump your 307 "peanut" cam. It is a smog type profile, and will just hold you back. If you want optimum mileage, run a stock 1973-80 350 Olds cam. For more performance with all stock parts, you should run a cam from 68-70 350, or even a big block. Use the 1970-80 Olds lifters for proper oiling.

Last, what year are those 330 heads? It may be necessary to grind or "slot" the pushrod holes in these heads to keep them from rubbing. The first 330 engines used a different angle for the lifters and pushrods, so the holes aren't properly aligned. You should also use the rocker arms that came with the heads if you have them.

Is there a thread for you to post this in? It is good to get this info out to the public when possible.

Let me know if you need anything else...

--Kris"

Feel free to comment! Thanks guys!

 

[beeterolds]

its funny how 330 heads work on a 307..when the 307s bore is 3.8 and the combustion chamber at its widest point is a tick over 3.9.. talk about lousy quench!!

If you want even a better cam choice.. why not a stock smog 455 cam>? at .435 .435 lift and 187-200 duration it would be a really torquey fun cam

 

[KrisW]

They DO work, regardless of technical aspects of quench or anything else. I have run them, and they are still superior to the smogger heads of the 80's with those horrible tiny ports.

Another option that I tried were some old 260 heads. I got them from my 76 Omega that had a 260 with the first dual jet two barrel carb that was made from a quadrajet casting with the back two secondary holes just cast in solid. The ports on those heads were just a little smaller than normal and all I had to do was gasket match them to the 350 smogger intake gasket. They also worked with the 307 and bumped up the compression I would imagine. They had small valves, though, but since I didn't change the cam I didn't figure it would matter. It ran great for just a stocker upgrade. I know the later 260 V8s had the little ports like the 307 but it seems the early ones were still okay.

I guess what I'm saying is sometimes the reality of the road test doesn't square with the mad scientist blueprints of the bench racer. Some times it is better, sometimes not, but when experimenting the most telling part of the experiment is the actual road and run test. No blueprint or formula can beat that.

 

[olds307 and 403]

Yah, anything for performance is better than 7A 307 heads. 330 heads are questionable heads to fit a 307 but are a good head. I used 5A heads with an SP2P intake on a stock 76 350 block with Corteco's and a,448/.472 cam in my 94 4X4 truck, with the low 4L60E first gear and a 3.73 open :? rear, it runs real hard. In a high rpm car, it would be a real turd. Depends what your looking for, most people the 5A heads ported and milled is good enough.

 

[apj87442]

Kris thanks for your help. I've had my 307 for years. It may not be the fastest but in this generation of coffee can mufflers and rice burners my 307 has always been cool IMO. Being on a budget evil bay has always helped out. 3.73 complete 7.5 even though open cost me $50.00 then add toll money and gas about $15.00 A dual exhuast w/h pipe and flowmasters w/turndowns($425.00) - $80.00 on used flowmasters alone, gasket matched a4 intake $47.00 still running strong and pontiac quadrajet #7045264 and old style distributor are the best. To some degree most of us are greedy for more power, some more than others no big deal though. Living in NYC and now NNJ it has become very hard to find older Olds parts and engines. Over here in this part of the U.S. most wreckers do not give a darn, if the car is old it's gong to the crusher. Just today I bought a 350 olds engine and 350 T.H. for $150.00 a good running combo. The roof of the 1978 delta 88 regency was crushed, it was on it's way out to the crusher today. It has the 3a heads. I may be upgrading to a motor that yes has more possibilities performance wise. One of my best deals ever. Six years ago my euro nose 87 cutty w/307 5a heads cost me $250.00 and to get a broker to register it for me$140.00. The previous owner had screwed up the titile rendering it defective. We all know of a good car or 2 that was junked for this reason. Under $400.00 one cool ride.
Now my non roller 307 runs in top form my tires chirp sometimes in 2nd gear. I acquired 2 sets of 330 heads,#1 and #3 each under 80 bucks. The idea of putting these heads on is what made me find this website. I think the 307 would do fine with them. I will do the 350 first though.
I hate to throw away good things and it sucks that sometimes these things get crushed. Why a 307? For me,I can find 4 of them for about $250.00 each and this guy is not pressing for space he's had them for years, second 330 heads are easier to find and alot cheaper than #5 or 7a heads. I'm on a budget but It doesnt really doesn't cost much to try this out. The 307 heads i think might be better than the 3a.

 

[apj87442]

the 5A heads I meant to say may be better.

 

[KrisW]

You've got a 350 now? Stop the presses!!

Those 330 heads are very choice stock pieces for your 350! On your smogger Olds V8, they will be good for nearly 10 to 1 compression ratio. that is awesome! Do that!

You will be happy you did. The best stock heads for your 350 from a small block will be the 330/350 heads up to 1970. After that they made the combustion chambers bigger to drop the CR to about 8.5:1 for most V8's. You can also run late 60's big block heads if you run flat top pistons with it, but you already have the good heads for a great running street engine now.

Now you just need a cam, intake, carb....

Good score, man!

 

[jae]

You've got a 350 now? Stop the presses!!

Those 330 heads are very choice stock pieces for your 350! On your smogger Olds V8, they will be good for nearly 10 to 1 compression ratio. that is awesome! Do that!

You will be happy you did. The best stock heads for your 350 from a small block will be the 330/350 heads up to 1970. After that they made the combustion chambers bigger to drop the CR to about 8.5:1 for most V8's...

Good score, man!

Actually Chris, you can run up to a '72 head (from #5, #6, #7 & #7a, with the 7a head the same as the 7 except for the hardened seats). Remember that Olds went to a dished piston in '71 but the 64cc chamber remained the same (I think the 330 heads had a 60cc chamber). I believe the chamber increased to 79 or so in '73, but the piston was not dished as much, if at all. I think the BB Olds had larger cc's to deal with the compression drop and most likely a dished piston as well - not 100% sure.

In any event, I agree with you - put the 330 heads on the 350 and have a blast!! 8)

 

[joe_padavano]

Actually Chris, you can run up to a '72 head (from #5, #6, #7 & #7a, with the 7a head the same as the 7 except for the hardened seats). Remember that Olds went to a dished piston in '71 but the 64cc chamber remained the same (I think the 330 heads had a 60cc chamber). I believe the chamber increased to 79 or so in '73, but the piston was not dished as much, if at all. I think the BB Olds had larger cc's to deal with the compression drop and most likely a dished piston as well - not 100% sure.

All Olds heads from the 1971 model year on used induction hardened valve seats to accommodate the federal mandate to operate on low-lead gas. No. 7 heads have hardened seats as well. The main difference between the No. 7 and 7A heads is the spring pockets. The No. 7 heads used valve rotators on the exhaust valves only so the exhaust valve spring pockets are cut deeper than the intakes. The 7A heads used rotators on both intake and exhaust, so the all the spring pockets are cut deep. And just to be clear, we're talking about the 7A heads, not the 7A heads. The chambers got big starting with the No. 8 heads in 1973.

With the exception of the 68-69 D heads, all BBO heads have the same 80-ish CC chambers. (D heads run 72 CCs). Note that 80 is the design volume. As-cast numbers tend to run a couple of CCs larger.

 

[KrisW]

The last BBO heads that I ran were "C" heads and they were awesome on a 350, late 70's, with new 69 350 OEM pistons. Just awesome. You can run the performer RPM intake and port match them and they work great.

Try to post some pics and time slips of your 350 with the 330 heads if you can.