71 spark knocks
New User
Joined: Sep 2000
Posts: 4
Likes: 0
71 spark knocks
Bought a long block to replace a windsor I put in my 71, had trouble with carb, installed new 600 elderbrock, has electronic ignition, it spark knocks taking off and under load, tried timing with light will hardly run, is 6 b.t.c about right. Not real sure off year of engine, block is a wc casting and I think heads are a wf, or visa versa, heads have square water jackets. The harmonic is from original 302, could it be a problem, engine does'nt have a vibration. Any help is appretiated. If I back off timing to remove knock engine has no power at all. Thanks.
Lead Driver
Joined: Feb 2000
Posts: 5,374
Likes: 46
From: Palm Bay, Florida
71 spark knocks
What engine do you have a 302, or a 351 windsor?
You may have the distributor in one tooth off.
Is your electronic ignition factory Duraspark? or an aftermarket? how about the air gap in the distributor? plug gap match everything else?
just fishing to see if we can help you.
-Supercab
You may have the distributor in one tooth off.
Is your electronic ignition factory Duraspark? or an aftermarket? how about the air gap in the distributor? plug gap match everything else?
just fishing to see if we can help you.
-Supercab
Junior User
Joined: Apr 2000
Posts: 89
Likes: 0
71 spark knocks
Try running premium fuel, it it doesn't knock then the C.R. is to high for the cheap gas. Run a compression check, if it's stock type cam you usually see 130 to 145 lbs, but that's not gospel.The new block may have flat top pistons where the old may have had dished ones.
Jim
Jim
