I have the normal 9.2:1 1968 350 in my coupe. For now it is pinging on anything but 93. I figure, shoot, if it's gonna use 93 at least let it be a higher compression engine.

Assuming that a head swap would do this for me, what heads would do the job? (When you stop laughing AT me, read on.)

Could I just mill the heads (deck?) a few thousandths and raise the compression that way? Is the higher compression asking too much of my two bolt mains and 37 year old rods?

Am I an idiot that should just buy a 400 HO engine and stop doing it half-a$$ed?

Why raise the compression? I bet some of the experts on this forum could help you choose a cam and exhaust upgrades that would improve your performance, assuming you have a four barrel.

And if you're going to swap the engine, why not go all the way to 455

ask these guys...
web page or just hang around and Q might answer....or Banshee...or THOCan....

not sure , but my buddy here in town w a 350 got his pretty peppy w a cam , and some exhaust
manifold..

Thanks, Bjorn ... your money will be in the bank on Monday.

Tom's right - get bigger valves and a longer duration cam, and all that detonation will go away ... far far away.

You don't need more compression ratio. On the contrary. You need to reduce the dynamic compression ratio with more cam duration, bigger valves, more intake and some better exhaust. Match the carb and distributor tuning to the combination, and your 350 will be far more fun than it is now, all on 91, 92 OR 93 octane.

The 350 HO cam is the 067 or 068. That's a good-sized cam for a 350, and can be picked up at places like Summit Racing as their part number SUM-K2801 for about $85 with lifters. Start there and let us know what you think.

Concerning exhaust I'd the luxury of saying I'm "done" with exhaust. The car has new all Flowmaster from the new Ram Air repro manifolds back. Apparently I ordered the leaky filter relocator by mistake when I got the manifolds. :p

The car used to have Hookers on it but they hung down way too low. The repro manifolds seeem to be a nice compromise. Yes?

Thanks for the tips gentlemen. I'm sure I'll be referring back to this thread later.

Does anyone have an extra adapter they can send to me? (It will be returned within one week.) I want to see what needs to be improved.

I am getting ready to put some V-8 stuff on the site, and I'd love to have that part, and make it right. (It can't be that hard to get it right.)

One of the other new things we'll be offering are super-tough, hardened & shot-peened oil pump drive shafts that you can drop in from the top. I've had them for years, but now I have an excuse to sell them.

Q, I have a home-made adapter that works fine you could "borrow" for awhile if interested. I believe mine is thicker than original, but worked fine on my '68. Let me know!

Steve

P.S. Smitty, try to ad a few washers between the adapter sounds like your bolts have bottomed out, making it impossible to get tight. I ran into that problem, too!

I was thinking that the block to adapter gasket might possibly be the culprit, depending on how the passages are lined up. I have a complete engine gasket set and there are no less than four versions of the oil filter to engine block gasket.

I see that I've hijacked my own filter thread.

Right now I have a Pocketfull of 3/8" lock washers. I'm going to put at least one on each of the bolts then sacrifice a chicken and two virgins to the 'Bird gods.

Wish me luck.

Steve - THANKS for the offer let's hope I don't have to take you up on it. More news later.

I have a spare 350HO service replacement distributor in the toolbox, if you're staying with points.

Great choice on the R.A.R.E. exhaust manifolds! I'll be doing the long branch manifolds this spring.

Thanks Yellowbird. However, converting to GM HEI was the very first thing that got swapped. I sure hope I can get the car painted by 1 June!

nice car smitty your bumper fits great, any tricks to getting it like that?

If Smitty were to swap engines to a 400, wouldn't he still be able to run 93 octane?

--Mike

What heads would Smitty run?

PMI - all those head numbers give me a brain cramp. Yep, I'd like to know which one might give me bigger valves and higher compression.

Chondro - I guess I got lucky. I haven't touched the bumper except for some polishing. I hear that some guys use shims (washers?) here and there to get bumpers to hang right.

Smitty -

You don't WANT higher compression. Trust me.

You want 9.2:1, like Banshee suggested. You want any of the heads listed by Banshee.

For a 350 the specifics you should be looking for in a set of heads are:

Large valves (2.11" Intake / 1.77" Exhaust)
Screw-in Studs
68-75cc combustion chambers
6 driled and tapped exhaust manifold bolt holes.

There is a LONG list of heads that meet these criteria. Some of them are astronomically expensive; most are not.

Thanks again for the advice PMI. I'll take it to heart (and my wallet.)

I went to your company's web site. Y'all definitely speak OHC engines. Impressive!