1970 Chevy Chevelle Engine cuts out and misses above 4000 R

PEDALCRAZY

MEMBER
1970 CHEVROLET CHEVELLE
V8
2WD
MANUAL
150 MILES

Hello, I have a 1970 454 LS6 that was recently totally rebuilt. It is rebuilt to correct specs and includes 11:1 compression, solid lifters and Holley carb. All corrct parts--nothing aftermarket. The distributor was rebuilt by distributor professional. It has points and condensor like it came from the factory with. The points are suppose to be the heavy duty ones rated for higher RPMs. The engine runs smooth up to about 4000 RPMs and then cuts out and sputters fighting to keep climbing. The red line is 6500 RPMs from the factory. What are your thoughts on possible problems? Thanks, Steve

Monday, October 26th, 2009 AT 4:53 PM

2 Replies

MICKEY-D

MECHANIC
304 POSTS

You did not mention your ignition coil. If its not new, replace it. You should check the dwell, it should be 28 to 32, 30 preferred, and it should not fluctuate much if any under acceleration. Have your distributor guy pull the dist out, and put it on his machine and show you that it will get to lets say 7500 RPM without the points floating. If nothing is found in the ignition, check you valve adjustment, if its got solids.
Good luck, I hope we were able to help you out.
Mickey-d

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Wednesday, December 2nd, 2009 AT 10:55 PM

PEDALCRAZY

MEMBER
2 POSTS

Thanks Mickey-D, I replaced the coil and verfied dwell at 30 degrees (which it was) and that did the trick! The coil was new (GM-not aftermarket) when the engine was assembled but it must have been bad right out of the box. The engine now screams past 4000 RPMs and runs and sounds like it should. Thanks much for your help and this great forum!

Steve

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Thursday, December 3rd, 2009 AT 9:07 AM