Questions about 260
Questions about 260
Most the restoration on the Comet was done two owners ago. I got paperwork on what was done but no details on the engine. It runs good and strong with a very lumpy idle. The carb is a 600 cfm Holley. The aluminum manifold has no identifying markings. The aluminum heads also have no markings I can find. Seems to me I can figure out cam duration and lift with a dial indicator. I guess I am asking for suggestions on how to figure out what was done without taking it apart. Would like to know compression ratio and valve sizes. Thx for any ideas.
Pat
1963 1/2 S-22 260/4spd
1963 1/2 S-22 260/4spd
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Joe Travers
- Posts: 2446
- Joined: Mon Sep 21, 2020 6:23 pm
- Location: Louisiana
Re: Questions about 260
If you have aluminum heads, my first question would be 'is it a 260'? Has a 260 timing chain cover.
260 has 3.8" bore, can't be bored to 4" for larger valves you would typically find in aluminum heads.
Five or six bolt bellhousing?
Joe
260 has 3.8" bore, can't be bored to 4" for larger valves you would typically find in aluminum heads.
Five or six bolt bellhousing?
Joe
1963 1/2 Custom Hardtop
342 stroker, solid roller, T-10, 3.55 posi
Re: Questions about 260
Thx Joe. It is a aluminum bell housing 5 bolt. So not a later 289. Did some internet study. Looks like hard to tell the difference between 260 and early 289. Looked at motor mounts freeze plugs casting numbers bell housings. There are differences with later 289s but early ones hard to say. Like you said lotta stuff going on in 63/64.
The one thing that might have been the answer would be the motor assembly date stamped on the block next to the water pump. But this motor was decked somewhere along the way so that marking is gone.
Going to set my questions aside until I have a good reason to open it up!
The one thing that might have been the answer would be the motor assembly date stamped on the block next to the water pump. But this motor was decked somewhere along the way so that marking is gone.
Going to set my questions aside until I have a good reason to open it up!
Pat
1963 1/2 S-22 260/4spd
1963 1/2 S-22 260/4spd
-
Joe Travers
- Posts: 2446
- Joined: Mon Sep 21, 2020 6:23 pm
- Location: Louisiana
Re: Questions about 260
Right, could be early 289 that was swapped in @ some point. The 5 bolt 289 was available in '63 Galaxie & Fairlane.
One tell for a stock 260, the piston is flat-top w/o valve reliefs. You can check that w/ a scope down a spark plug hole if you're still curious.
If the camshaft has been changed, bets may be off on that one. Many years ago, Shelby offered a modified 260 piston for use with the HP solid lift cam.
Stock 260 pistons could be cut for valve relief if someone was really hard up to keep stock displacement.
It's such a rare car, it wouldn't surprise me.
Joe
One tell for a stock 260, the piston is flat-top w/o valve reliefs. You can check that w/ a scope down a spark plug hole if you're still curious.
If the camshaft has been changed, bets may be off on that one. Many years ago, Shelby offered a modified 260 piston for use with the HP solid lift cam.
Stock 260 pistons could be cut for valve relief if someone was really hard up to keep stock displacement.
It's such a rare car, it wouldn't surprise me.
Joe
1963 1/2 Custom Hardtop
342 stroker, solid roller, T-10, 3.55 posi