Holley Carb Tuning Problems --- Help

[CdnCutlass]

Have you tried the plugs yet?? No 450 hp isn't too much but you need the right parts and those parts all have to work together. Cam, intake, carb, torque converter, rear end, have to be matched for your combo. You are currently set up for bottom end and your package pretty much matches with the exception of the big heads. Your engine isn't much above stock; you have a point more compression and a little more cam so right now 450 hp is a stretch.

The plugs are brand new champion RC12YC. Previously I had an NGK racing plugs in which were recommended on the head spec card. No difference between either.

 

[CdnCutlass]

Looking more closely at the rockers with the valve covers off the ones that are not under load wiggle side to side. Is this play in the rockers normal?

 

[crucial118]

Were the heads new?

 

[CdnCutlass]

Were the heads new?

Yes they were brand new with the motor. About 1500 - 2000 miles on them in total.

 

[crotchss]

Yes sir, slight movement back and forth when not under load is normal.

 

[CdnCutlass]

Yes sir, slight movement back and forth when not under load is normal.

That's a relief. Looking at possibly putting a more streetable set of cylinder heads on over the winter. I was leaning to something in the 180cc size category. Any recommendations?

 

[Fox80]

http://www.dartheads.com/products/iron- ... heads.html


Dart iron eagles are a very good head, I have used the 180cc on a 355 and a larger set on a 430 and loved them both for street/strip type setup, they also make the SS for a more stock replacement application. Dart is also a great company to deal with should problems or questions arise, a call to the tech department with your specs would also be a good idea to get you headed in the right direction

 

[CdnCutlass]

Should mention I finally drove around with a fuel pressure gauge hooked up. No issues with fuel pressure dropping off at high rpm. Eliminated that as a potential problem.

 

[CWPottenger]

Car is running pretty decent right now. 16 degrees initial, 36 total timing. 72/75 jets with a silver secondary spring and 3.5 powervalve. Currently have a 28 squirter. Trying to determine if it is rich or lean off idle.

I can get to 5500rpm without issues before there is some popping. Less than before with the leaner jets. I just filled the tank with 89 octane instead of the 91 I typically run and it had no affect on the high rpm issue. It makes me think if it was detonation it would have gotten worse with lower octane fuel.

Re-reading through this post... Did you actually switch to a 3.5 powervalve or is that a typo? If so that is too low for one. Also a 28 squirter might be small for your setup. I have a 383SBC and I had to jump to a 32 squirter to get enough fuel flow off idle to get rid of bog.

 

[CdnCutlass]

Car is running pretty decent right now. 16 degrees initial, 36 total timing. 72/75 jets with a silver secondary spring and 3.5 powervalve. Currently have a 28 squirter. Trying to determine if it is rich or lean off idle.

I can get to 5500rpm without issues before there is some popping. Less than before with the leaner jets. I just filled the tank with 89 octane instead of the 91 I typically run and it had no affect on the high rpm issue. It makes me think if it was detonation it would have gotten worse with lower octane fuel.

Re-reading through this post... Did you actually switch to a 3.5 powervalve or is that a typo? If so that is too low for one. Also a 28 squirter might be small for your setup. I have a 383SBC and I had to jump to a 32 squirter to get enough fuel flow off idle to get rid of bog.

Yes I have a 3.5 power valve. The vacuum in gear is only 7-8 inches if it stays running. Holley says divide that number by two and that is the correct size power valve.