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Distributor differences Big cap aftermarket, OE Small
Still on the '72 454. PO had this engine rebuild about 4 k miles back....yeh it's taken us 5 years to put that on her. Pretty mild build, roller tip rockers, externally fully desmog, non-a.i.r exhaust manifolds (factory without ports). I had so much other work on the car that I hadn't got into the dizzy, but I wanted to remove aftermarket HEI for looks. Put the pretty chrome cover on. I grabbed a used 71 points dizzy, put pertronix in it, went to swap, and wow, two very different dizzies. Chinese HEI has a wider timing baseplate/cap. When inserted into block, it indexes several degrees advanced of where the stock dizzy indexes.
Base timing is what it is so I'm not worried about moving the OE around to get base right, but what does the different circumference in the actual cap/rotor mean for general running? Does the increased rotor length make up for the extra distance between towers in the cap?
Yes.
It means nothing for general running......both can be setup to run equally as well.
I don't like HEI units becasue of their physical size under the hood of a Vette......
And when you set timing.....set for total timing (about 36-38 degrees) vacuum advance unhooked.
Yes.
It means nothing for general running......both can be setup to run equally as well.
I don't like HEI units becasue of their physical size under the hood of a Vette......
And when you set timing.....set for total timing (about 36-38 degrees) vacuum advance unhooked.
Jebby
Awesome, thanks for the info. My initial reason was same as you noted, huge and doesn't allow chrome cover installation. When I got in I realized I didn't need to swap my tach cable as I though I needed to, the drive gear in the dizzy for tach was ground up. Not the two pieces of replacement gear we buy and put on from outside, but the internal gear on the shaft that it meshes with. I actually like points because they rarely fail 'without warning', and immune to EMP. . I still did pertronix instead of points though, I may regret that...
Awesome, thanks for the info. My initial reason was same as you noted, huge and doesn't allow chrome cover installation. When I got in I realized I didn't need to swap my tach cable as I though I needed to, the drive gear in the dizzy for tach was ground up. Not the two pieces of replacement gear we buy and put on from outside, but the internal gear on the shaft that it meshes with. I actually like points because they rarely fail 'without warning', and immune to EMP. . I still did pertronix instead of points though, I may regret that...
Agree with keeping the points! These points replacement widgets always seem to fail when you are miles from home or in a bad storm somewhere. Has happened to me 2 times so I went back to good old points distributors years ago!
One reason for increased cap size is to help prevent cross firing between cylinders. Increased size equals more distance between posts so less chance of the adjacent cylinders getting some of that spark. Not really applicable to street cars though.
Distributor differences Big cap aftermarket, OE Small
. I still did pertronix instead of points though, I may regret that...
