I've got a Holley HP950 carb sitting on top of my 402 BBC. I moved to a new part of the state and went from sea level to 1,200' elevation at my new house. The carb was chassis dyno tuned for maximum HP at the track, with 78/90 jets, from the stock 78/78 square. The carb is running way too rich at this altitude.

I don't drag race the Chevelle anymore, and wanted to get the jetting down to a reasonable level for cruising. I don't have access to a chassis dyno anymore, so I figured I'd just do it the old fashioned way, seat of the paints tuning.

I pulled the bowls off and re-jetted the carb down to a 76/80. When I went to put the bowls back on I found the rear lower passenger side bolt was just spinnning. I pulled the carb off and found the threads were stripped out of the body of the carb on that hole.

Anyone have any suggestions as to how to proceed with this mess? Unfortunately this carb only has about 3,000 miles on it. I have a tendancy to over-torque aluminum. :rolleyes:

I've been kicking around switching out carbs, anyway. I know the HP950 is more than likely too big for this motor, for cruising purposes. I've been kicking around getting a 750DP for the car, and milling off the feedhorn, or getting one of those Proform bodies for it. I think the HP950 would kick butt on my 454 I'm building for my '78 Malibu drag car.

I guess now's the time to get things set straight. Any ideas on how to repair the HP950, and any suggestions on a carb for my 70 SS would be greatly appreciated. Info on the 70 SS can be found in the link in my signature. The only info missing in the TC write-up is that my 781 heads have 2.19/1.88 valves.

Thanks!

You can get a helicoil kit to fix the bowl screws. Holley sells it. It is an unusual size 1/4 x 24 I think. I have repaired many of them for customers, its an easy fix.
Hope this helps,

It does solve one problem. Anyone wanna take a stab at a carb recommendation for the 70 SS396?

700 cfm spreadbore Holley...do they still make spreadbore Holleys?? I had one of those on a 402 then 427 for a while.

I said to heck with it and just went with the ol' dependable Holley 750DP...

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=2480161362&sspagename=STRK%3AMEWN%3AIT

Got a brand new 750 DP for $275. Not bad. My altitude is 1,400' not 1,200'... and in street trim she's just running too rich with the HP950. I should be just fine with this carb.

Thanks for the help. Oh, also, I went through my Holley catalog and found a set of helicoils for the main body. Holley part #26-2, it's pretty spendy, $70. from summit.

Sean,that sure is a funky looking 750 double pumper..my list number is 4779..

Sean, with the carb you bought off of ebay being setup for a 2x4 setup you just might run into it being rich at idle. I went through that with a 1050 I bought.

I am lucky enough to have someone guiding me through changing the airbleeds ( not removeable now, but will be) to fix this correctly and return it to be better suited for a 1x4 setup.

SS_Sean,

Let us know how you make out, that picture looks a lot more like a single feed 4160 carb then it does a 750 DP.

No, it was a 4150, but it's a application specific 2x4 carb. Chris called it on the money. I didn't have the carb listed in my holley catalog, and I don't have time to mess with oddball crap, so I asked the seller if I could back out of the auction and offered to pay the seller his auction fee. It looks like we have an agreement. I bit and won on a 4779 750 DP. Thanks for the heads up, Chris. The 750cfm carb will work great up at this altitude, and with me not racing the Chevelle anymore. Thanks, guys (once again)!!