[Rich72C10]

A bit of a update. I was reading another thread where someone recommended Cliffs High Performance Quadrajets. What a super nice fellow and seems to be crazy smart / knowledgeable about Qjets and SBC! I have gotten more information out of Cliff in a few emails then I got from Mark/Quadrajet Power in nearly a year. He also gets "repaired" Quadrajet Power carbs that Mark has messed up, so I am not the only one it seems.

Direct Quote from Cliff after he asked a bunch of question about my engine:

Your problems are two fold here.

993 heads are EXCELLENT for flow but have 76cc chambers.

You used “builder” 350 pistons which are dished and typically around .025-.035” in the holes at TDC. The head gaskets were most likely from a standard “kit” so would have been at least .040” and possible even .050-.060” thick. So quench is far from ideal and in the .055-.095” range someplace instead of .035-.038”.

Then you put in a larger “RV” cam, most are 204/214/112LSA.

The original engine had the pistons .015-.018” below the deck at TDC and .020” steel shim head gaskets for .035-.038” quench. This yielded about 8.2 to 8.5 to 1 compression with the factory dished pistons. Cam was 194/204 duration so it made great vacuum, butt loads of low end power and strong mid-range power.

The pistons and head gaskets used for your “build” LOWERED the compression ratio quite a bit. Not your fault, even the most skilled machine shops do this ALL THE TIME. They don’t know about all that stuff, they just machine engine components and sell parts to go with them. It’s probably down around 7.5-7.7 to 1 or so. Add a larger cam and it will be “soft” at lower RPM’s, but still shine pretty decent from about 2500-4800rpm’s or so.

The lower compression deal REQUIRES more timing and fuel to keep things happy.

Then you trumped the entire deal with “remanufactured” carburetors. Cripe, I can NOT make them work well without considerable effort as they are “butchered” all to chit and not using stock specs anyplace.

After telling him that I got my Rochester Quadrajet 7042208 from USA Carburetors he told me this:

USA carburetors is BOTTOM of the barrel and probably why Mark couldn’t do anything with it either, they are “hacked” pretty hard and often butchered up enough difficult to get working correctly.

This is what he told me about Quadrajet Power / Mark:

Mark wasn’t able to get it done, and he’s better than most. I still get a few of his carbs in here on occasion with fundamental issues. Did two last month one was leaking under the seat due to a “crater” where the gasket seals. Another one for a stout 355 SBC in a 1970 Nova just wasn’t calibrated close enough for the larger cam the guy decided to install in it.

After all this is still thinks he can get my Rochester Quadrajet 7042208 running properly but does think I should just start over (because it came from USA Carburetors but I don't know where to find a good 7042208 core). Heck his cost is only like 1/3 of what Quadrajet Power charged me and 5 months faster to get to it too. I wished I'd find this guy before even starting the rebuild of my SBC 350!

So I am going to give this a try .... like I told him, in for a penny, in for a pound LOL

Edit: though it seems the piston installed look like the ones that came out of my engine.