Sluggish 451

[Garys1969RR]

I recently got a 65 Belvedere that has the Eddy Performer RPM heads, headers, Holley Street Dominator Intake with a 3310 Holley carb, and a fairly mild cam. .480 lift, 280 duration. It also has 4.30 gears, and a full manual 727 T/Flite trans. Getting 210 to 220 PSI cranking compression. This thing will not break the tires loose in 1st gear! Just re built the distributor, new pick up and inductor wheel. That cured the higher RPM miss, but still weak on power output. Could a faulty coil cause this? I can swap the one off my RR to see if that helps. Bout ready to pull a head to check C/R, gasket thickness. I suppose a leakdown test would be a good place to continue the diagnosis. Sounds real healthy, good ex note and no smoke. Any ideas?

 

[Badvert65]

coil and/or timing could be a definite possibility.

 

[Garys1969RR]

My 69 RR 451 is built about the same, except 509 cam, 915 heads, same intake/carb. High Compression. The RR motor will break the tires loose in 1st and 2nd. Way faster, 3.91 gears, engine totally roars under acceleration. Only difference is heads, ( The Eddys should be better). Different header type. Belvedere has 1 7/8 primary as opposed to 2" on the RR.

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coil and/or timing could be a definite possibility.

Ignition Timing on both motors is 38 total.

 

[eric383]

Make sure the carb is wide open when the throttle pedal is all the way down. Just my 2 cents worth.

 

[ga66mopar]

I wonder if the cam was degree in when it was installed. Even when the dots are lined up the cam can be advanced or retarded a few degrees. Sounds like the cam could be retarded a few degrees which will make it a little soft on the bottom end. I learned my lesson the hard way about not degreeing the cam in.

 

[Garys1969RR]

Yea looks like may have to pull it apart some to check specs. May change the cam at some point, but should have a lot of low end with this one, but it doesn't.

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I think a leak down check would help.

 

[Hemi Rebel]

Where is your timing set? What torque converter stall speed? At 210-220 psi on a compression test, a leakdown test is a waste of time.

 

[daredevil]

Timing gears one tooth off can cause this also.

 

[natas33]

what cam, brand? what size headers? what static compression ratio of the engine? what ignition box?

 

[HT413]

Maybe it's really just a 400.

 

[Garys1969RR]

Maybe it's really just a 400.

Yea you know, 413, it runs about like my 67 Satellite with a 400 engine and 452 heads! And the Satellite has 2.76 gears, while the 65 has 4.30s. So I am suspecting the cam timing is off a tooth. It has a real strong exhaust note, like if the cam was advanced 1 tooth, it would open the ex valve way early, causing a strong surge of ex gas out the headers. Thats what its doing. It will actually blast your hand back at an idle.

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And the 65 has Eddy perf RPM heads on it! Definitely has some strong exhaust flow.

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Advanced 1 tooth would also account for the too high compression readings. Due to the intake valve closing way early. Guess it's about time to pull the front timing cover and take a look!

 

[747mopar]

I agree, I'd just go threw one thing at a time. Confirm fuel delivery, ignition timing and then cam timing. I have a 451 as well with a mild cam (501"), 160 cranking psi and it will melt the tires with 3:55s so definitely sounds like something is off.

 

[Cranky]

Here's something I got from Dan Dvorak awhile back.....never tired it myself so I don't know if it works or not....

HERE'S A LITTLE QUICK CHECK CHECK FOR YOU ALL WHO DON'T KNOW WHERE YOUR CAM IS....... and it's extremely helpful to have adjustable rockers (if you don't you'll never get the engine to smooth out anyway) (1) pick a cylinder (2) adjust both valves the best you can to .012 and .012 on the sweet spot, the best spot you can find then (3) bring the cylinder to TDC firing stroke. (4) measure the existing lash it won't be .012. If the intake is tighter than the exhaust the cam is advanced. If the exhaust is tighter than the intake the cam is retarded. If they are both the same, the cam is straight up.

 

[ibsorgn]

Here's something I got from Dan Dvorak awhile back.....never tired it myself so I don't know if it works or not....

HERE'S A LITTLE QUICK CHECK CHECK FOR YOU ALL WHO DON'T KNOW WHERE YOUR CAM IS....... and it's extremely helpful to have adjustable rockers (if you don't you'll never get the engine to smooth out anyway) (1) pick a cylinder (2) adjust both valves the best you can to .012 and .012 on the sweet spot, the best spot you can find then (3) bring the cylinder to TDC firing stroke. (4) measure the existing lash it won't be .012. If the intake is tighter than the exhaust the cam is advanced. If the exhaust is tighter than the intake the cam is retarded. If they are both the same, the cam is straight up.

Very clever