Thunderbolt iv question

[twofiftyeight]

Can someone tell me the difference between these ignition modules? Both are on ebay and say that they are for a 454. Is one just an older style?..Are they interchangeable? Does a 5.7 of similar year use the same module?

I'm in need of a TBIV module for my carbed 454 going in the Hornet so if anyone has one that they'd like to get rid of please let me know.

Thanks!

http://i158.photobucket.com/albums/t112/xiduse42/7fec_1.jpg
http://i158.photobucket.com/albums/t112/xiduse42/3a3d_1.jpg

[HOWARD O]

Yep, I'd say different styles. I am using the one with the triangular plate which originally came off my 1982 Wellcraft with a 454. On the module itself, it says V8-24. The triangular plate was mounted on the side of the exhaust manifold, although I found another spot on the block, near the distributor.

The other is newer and you would have to find a reference for the numbers if it doesn't say V8-24 (or V8-22, etc.). The "24" or whatever is past the "V8-" designates total advance timing, minus initial advance.

Can't answer whether a 5.7 is interchangeable. I am thinking no, perhaps an old fart boat mechanic could chime in on that one.

[MOP]

Yes they will both work, there are different advance curves. On light boats with little loads I do not think the curve is as important as it is on heavy boats. The distributor with fit both SB & BB, I am running the old style R square box with 24 advance using 10 as my base timing.