Since we have talked lately about what would you swap in and what would you yada yada..... Let's talk about maximizing what we have available to us.

My 345 runs well now but the lifters tick badly, it is fouling the plugs, and the front and rear of the engine leaks pretty bad sometimes....but hey...its an IH!!!

Here's my hypothetical:

I have a 345 short block I bought at a farm auction in a crate and bag for $10. It has been bored .030, crank was turned...yada yada by a very reputable local shop. What would you do to this motor for max offroad grunt?

Parts I have in/on my current 345 to swap over from top to bottom:

795 Quadrajet
4bbl intake
Jacob's Omnimagnum
Coated Tri-y's
Comp Cams 268H cam
8mm Accel wires
Dual pipes to dual mufflers
One heat range hotter plugs

What would you keep and what would you replace and with what would you replace it? Different cam, HEI conversion, dual pipes to one muffler and one single exhaust pipe, crossover pipe, different/smaller carb, etc....

How about it? I may have missed this in the archives but I have done a http://www.pirate4x4.com/forum/images/top_search.gif without any info besides Tom's 345 buildup page and a few others. How about it from the :vader: :skull: side?

Originally posted by YellowIH

My 345 runs well now but the lifters tick badly, it is fouling the plugs, and the front and rear of the engine leaks pretty bad sometimes....but hey...its an IH!!!


Probably have shot cam bearings.. that's a good reason for the lifter tick.


What would you do to this motor for max offroad grunt?

Comp Cams 268H cam

What would you keep and what would you replace and with what would you replace it? Different cam, HEI conversion, dual pipes to one muffler and one single exhaust pipe, crossover pipe, different/smaller carb, etc....


Port the heads, less cam (my race Scout only runs a 262), more valve spring.

Balance, deck it to bring up compression a little. Balance it so it's happy spinning 6000rpm.

Oh yeah.. make sure you put NEW CAM BEARINGS IN..

Yeah, what Tom said,

Plus make sure the block is decked, even if it means sending it back to the machine shop. Shoot for zero deck height (pistons level with the top of the block and @ 9.3 to 9.5 to one compression. If the heads are already milled too bad.

As Tom said the Comp 268 is too much, meaning too much duration. I had a 260 Comp and it was too much. My new engine is very similar to yours and I went with a Schnieder 208/214 duration and .464/.472 lift cam. Should make good vacuum, idle smooth and make tons of torque with max at @ 2,800. It will still rev to 6K but I suggest staying under 5,500. Those are cast pistons, ya know.

oh and, BB Chebby valve springs work great.

can always go witha lighter piston - more likely a custom one even lighten the crank if ya wanted to spend the $$$
I'd recommend trying a carb in the 600cfm range and recurving the distributor

FUEL INJECTION! :)