DouglasOliver

I have a '66 cutlass convertible with a 330 engine, 4bbl carb, 350 trans, a mild after-market tow cam and headers.

I've been burning oil recently and I learned yesterday that I need new valve guides. so, unfortunately, I have to go through the expense of taking the heads off to repair them.

While I'm at it, I thought it might be worthwhile to make a few upgrades to other things as well to ensure that I never have to remove the heads again. My mechanic recommended three things:

1.) pc valve seals instead of standard seals

2.) port and polish the valve seats

3.) shave .022 off of the heads for higher compression.

4.) roller rockers

I'm not looking to create a race car here. I just want a regular street car with a little extra umph. But for the expense of removing heads, I figured I might as well pick up all the extra horse power I can get.

Do these upgrades make sense? Will any of them give me any noticeable performance improvement?

Thanks for any advice u can give me.

Doug

oldcutlass

The head work seems appropriate. The roller rockers, probably is not required for simplicity sake. What headers are you running?

DouglasOliver

Thanks for the reply. If there's no need for roller rockers, then I'll skip that.

As for the headers, they are just standard sized. It was hard to find headers for it and I bought some that didn't fit. I ended up having someone force them to fit by making necessary modifications. Mondello is the only place I know that makes headers for the 330, but they're kind of pricey. Maybe I'll get hem one day, but for the time being, I have standard sized headers. They seem to work well.

I just want to make sure that if I'm taking the heads off to do work, I get the most out of the car for the time and money.

captjim

330s already have pretty high compression, be careful that you do not end up too high. However, the gasket that you replace it with is probably going to to thicker.

"port and polish the valve seats"
I'm not really sure what this means? You don't need anything polished, a little bowl work, the dividers welded, and crossover filled would help you realize the benefits of the headers.

No need for roller rockers on a small cam but you will need to check pushrod length after the valve job.

oldcutlass

I understood the term port and polish, and shaving the head will compensate for the thicker gaskets that are around today. Make sure he checks the fit of the intake when he's done.

captjim

In all my years in this field I have never heard the term "port and polish the VALVE SEATS" I know what porting and polishing is. Polishing is money wasted and a good port job is well worth the money, hence my suggestion to get some bowl work done. Hogging out the ports will do more harm than good.

If shaving the head makes up for the difference in head gasket thickness, how will the intake be affected? How will the builder check the fit of the intake when he is only doing the heads? And even so, trimming .030 off the heads will not cause a problem.

DouglasOliver

I was told that shaving the heads by only .022 wouldn't require thicker head gaskets as an offset. Either way, I only want to do it if the additional horsepower from the higher compression is noticeable.

If the consequence of more compression is that I have to burn higher octane gas (more $), then I probably won't shave the heads at all.

As for porting, (regardless of polishing) it seems like everyone generally agrees that it makes sense to do while the heads are off.

jensenracing77

he is referring to the fact that the replacement head gaskets are thicker than the ones that they used originally. If your gaskets are original you will be putting thicker ones back on it just by replacing them.

DouglasOliver

makes sense. Thanks.