Accessory Bolt Holes for Camel Hump Heads???
 

Has anyone welded nuts or even drilled and tapped holes to install "accessory bolts" on camel hump heads?

I'm toying with adding a supercharger that requires those mount points but don't want to give up my nice, modified camel hump heads.

Seems that with a template, it would be fairly easy to weld some nuts to the heads. Can it be done without removing the heads? Do the fronts of "accessory bolt" heads project out to the same point as a camel hump head, or would I be able to account for this?

Would like to hear from anyone with experience.

I think I would consider some custom made brackets for mounting to exisiting bolts on the block. Maybe billet? This could look really trick and eliminate any problems with the welds or wanting to go back to original.

Buy some of summits new aftermarket cast heads. they outperform the original camel hump heads and have accesory holes

ci heads
 

successfully welding anything to cast iron heads is at best a crap shoot. I would not have any confidence with any welds for mounting. Just repairing a crack is a hit and miss operation. Aftermarket heads is the way to go.
Don

Yes, I have tapped a hole into the camel hump heads for mounting purposes. But I also made a spacer (out of aluminum) that conformed to the head contour, and then provided a flat face for whatever I was mounting (acted like a removable boss). Time consuming to make the spacer, but worked like a charm for many years on a daily driven street vehicle.

I would not try welding anything to the cast iron of the head. It is possible with a high nickel content rod, but then head should be preheated, etc., and then always the possibility of warpage.

Plasticman

I did it once. Made a template and drilled and tapped the holes. I didn't do anything fancy like Plasticman. I just used washers for proper spacing. I'm not real proud of it but it ran for a long time with no problems.

well.......... if your adding a supercharger, i surely would get some aftermarket high flow alum heads (why cut up a good set of originals???)

Thanks, Plast and Mike. How deep can one SAFELY drill into the heads to tap a thread?

As for those who responded that I should change heads, I see no need to add an additional $1,000+ to the project. My heads were "cut up" long ago, if that's what you call professional pocket porting, port matching, hardened seats, and 3-angle valve job. Car does about 300 hp at the wheels (293 on the dyno prior to a Lars tune-up and some carb work), so there is really nothing wrong with these heads that warrants the addional $$$ outlay.http://forums.corvetteforum.com/phot...o_Pull-med.jpg

Just because I now think you are serious, I'd like to add something. If you are going to hang a blower off these added holes, I'd give this some serious thought. I don't remember what I used the added holes for, only that I was using a set of 64 cc heads to raise the compression on my pitifully slow new '71 pickup. A blower running under boost would have much more strain on these attachments than what I was doing. If you do this, make sure everything is square and not in a bind. Just using flat washers against the cast surface of the head would probably not be a good idea for something that had a lot of strain against it. no reason the washers couldn't be brazed to the head. You could probably use a four inch grinder to flatten the cast surface of your heads to make sure your barcket was against a flat surface.

As far as drilling too far, I see no reason you can't go into the water jackets and use Permatex to seal the thread holes. Just don't drill into the combustion chamber. You may want to use studs in the heads instead of bolts.

If you want to return the heads to stock configuration, all you have to do is put the right head on the left and the left on the right.

Please promise me you will tell NOONE I told you you could do do this! :D

I agree that a supercharger will add to the stress! The holes I added were used for mounting an alternator (a lot less stress). As for depth, I did a bit of measuring and did not protrude into a water jacket or oil area. I will estimate (from a failing memory and a long time ago), that the holes were about 1/2" deep or more (deep enough for proper thread engagement on a 3/8"-16 bolt). Studs are an excellant suggestion, but may cause other mounting problems. As long as the mount ties in with at least 2 points (3 is better) on the head, and also off the water pump mounting bolts, I would think that should work with a supercharger.

When working with holes that are of minimum depth, you will need to finish off the threads with a "bottoming" tap, so you get threads pretty close to the bottom of the hole for max thread engagement.

However, a better question is what compression ratio are you planning on running with the supercharger? I added a Paxton supercharger to a SBC (on a buddy's 66 Avanti II) using the above mounting points, but the heads were later models (we needed a lower compression ratio) with the front mounting holes.

In other words, you may think about changing over to later model heads for the same reason (lower the compression ratio for the supercharger and gain the mounting points all at once). Some of the 70's & 80's era iron SBC heads are decent for that application (and some are terrible!). You probably want about a 9:1 compression ratio depending upon boost (the higher the boost, the lower the ratio should be - or use very high octane fuel). You would also gain the induction hardened valve seats that are probably a necessity for blower usage.

My twin turbo'd boat ran 8.5:1 CR with up to 7 pounds boost, and had a knock sensor, which warned me when I was detonating. Still went through an engine - cracked piston from detonation (but 72 MPH in a pretty heavy 23' cruiser with a 350 SBC was impressive).

Good luck on your project.
plasticman

but 72 MPH in a pretty heavy 23' cruiser with a 350 SBC was impressive).


I think I told you this once before. Impressive!

Thanks guys, compression was reduced to 9.5:1 when the heads were done. A bit high for a blower, not not incredably.

I'm considering the Procharger unit that looks like the old fuelie setup and sits in the center above the intake manifold, and I believe that the system ties in to both heads, so it doesn't put the strain on a single head like a side-hung unit. The blower is designed to mount to a ZZ-4.

What I did for the mounts needed with a serpentine belt conversion was to bore 1/2" diameter holes where I needed and then made threaded 1/2 diameter spacers that were TIG welded in places with high nickel rod. A little work with a dremel tool to turn the welds into fillets and they now look like they were cast that way.

Check the street rod and hot rod magazines.

There are some very nice accessory drive brackets available now. I'm sure you can even get one custom made.

It would look better and be stronger than mangling your heads.

Heads
 

what if you just want to run your alernator and change them into the 1969 and 1970 heads.

This thread is really old, your best bet would be to start a new one with your question.