260-302 stroker

[six4caliente]

I was in my buddy's shop last week, and he has about ten 302 cranks and a bunch of sets of rods. would a 302 crank and rods fit in my 260? If my calculations are correct, my .040 over 260 block with 302 rods and crank would be a 278 stroker. I would be able to squeeze a few more horses out of my original block

ben.

[six4caliente]

http://www.bgsoflex.com/cgi-bin/displac ... ode=Inches

[CALIFORNIA CALIENTE]

Ben;I would say yes because the 260 and 289 share the same crank.If you can borrow one to test fit would be a major help.,you need one rod also as you want to check crank and rod clearance at the bottom of the cylinders. ROY.

[six4caliente]

thanks for the input roy. i wasn't sure if "hard core performance" was teh place to ask about 278 cubes of power but the heading said "unusual and unique performance mods" and i think it fits that!

ben.

[CALIFORNIA CALIENTE]

Ben;if it works out it will be a cool little engine.The next hurtle will be heads as that small bore limits you to heads with small valves,but I think 289-302 heads will work with stock valve sizes,maybe even early 351 valve sizes.I would stay away from any heads with a combustion chamber bigger than 60cc,early 289's have a 58cc chamber which I feel would work well.I say GO FOR IT!!! ROY.

[six4caliente]

sorry to dig this one back up... but this stroker idea is looking more and more likely. do you think the stock valved gt40 heads would fit?

ben.

[65 hipo]

Yes the GT40 head would been fine. There going to be little of a difference in cubes. What cam, intake and crab are you going to run?

[six4caliente]

i know that they will bolt on, but do you guys think the GT40 valves will clear the cylinder walls (keep in mind im running a 260...)

[juddp39532]

I wonder what differences are in 302 gt40 head and 260 chambers and the efect on compression?

[six4caliente]

my 289 heads have 54.5cc chambers with 1.67"intake 1.45"exhaust.

gt40's that i would like have 62cc chambers and 1.84"intake 1.54"exhaust.

the question remains-would valves that large hit the cylinder wall on my 3.8" bore 260...

ben.

[Rick Shipley]

Sorry to dig this old stuff up, but I read an artical a few years back that said that stroking of any kind was risky because the 289's and 260's cylinders did not extend down far enough. This caused the piston to become unstable in the bore at BDC.
Has anyone heard anymore about this?

[CALIFORNIA CALIENTE]

Rick;I think that is an old wives tale!!! There must be a million 347" stroked 289-302s running around,mine is going on 15 years.One thing you need to check is available pistons,you may be stuck using 260 pistons with a custon length rod.I would set a crank in the block and set a piston at the top of its travel and measure between the piston pin center and center of crank throw.You also need to check rod cap bolt to bottom of cylinder clearance,like you need to notch them for a 347 stroker.You also need to check piston skirt to crank counter weight clearance.A;ll this may sound like a big problem but you may find a rod-piston combo off the shelf that works.If you can get a GT40 head to borrow and set on your block,then look up into the bore and see if the valves clear. ROY.

[Rick Shipley]

Maybe I should have explaind differantly, I think this was talking about the early 260 and 289. I took it to mean the 5 bolt motors. Would this make any differance?
I'm sure that RPm has to figured into this too. No more 7200RPM shifts
I've never done the stoke thing. I've always been too scared of the piston speed