350/290 hp crate motor
Thread Starter
Racer
Joined: Apr 2007
Posts: 275
Likes: 1
From: Lafayette/marquez La/tx
350/290 hp crate motor
I installed a 350/290hp crate motor bout a year ago. Alll of a sudden I get poor performance. I did a compression test. All 8 cyl. read 125 psi. This seems low to me. Any ideas?
Team Owner
Joined: Aug 2006
Posts: 24,125
Likes: 15
From: Columbia Missouri
That does seem a bit low, I would think you'd want closer to 150 but that's just a guess.
They are all uniform correct? Try squirting some oil in the cylinders before the compression test of each cylinder and see if the number goes up.
Have you done a leak down test to check for valve seal quality?
When was the last time the engine was timed, and have you looked for a vacuum leak?
They are all uniform correct? Try squirting some oil in the cylinders before the compression test of each cylinder and see if the number goes up.
Have you done a leak down test to check for valve seal quality?
When was the last time the engine was timed, and have you looked for a vacuum leak?
Le Mans Master
Joined: Aug 2003
Posts: 7,720
Likes: 12
From: Chattanooga TN
Compression sounds OK. I would look at timing,points, fuel pressure/filter, if you have a Catalytic converter it may be stopped up, might need a carb adjustment, if you have a Holley look at the power valve. How did the plugs look when you pulled them? What exactly do you mean by poor performance?
Thread Starter
Racer
Joined: Apr 2007
Posts: 275
Likes: 1
From: Lafayette/marquez La/tx
I installed a performer manifold, edelbock 750 carb, summit distrib, msd ignition and headers. Timing set @10deg. vac.is 13hg. It just runs rough has hesitation on take off. sometimes poping through carb.
Thread Starter
Racer
Joined: Apr 2007
Posts: 275
Likes: 1
From: Lafayette/marquez La/tx
I adjusted valves, set timing which i'm guessing at. Summit told me to set timing at 10 degrees. I found the intake gasket was leaking, changed that. Unplugged all vac. lines capped them off reading did not improve. This has me baffled.
