392 Trail Rig Build

[FishWagon]

Hello folks,

I also posted this on IHO, so excuse repeat if you saw it over there as well.

I have torn down a non-ic 392 I acquired to start a build for my trail-queen Scout Traveler.

Any comments would be appreciated. This vehicle will never see cruising speeds.

Some info on the rig first:

1. 14bolt rear/Dana 60 front, both Detroit locked, 5.13 gears turning 40" tires

2. Transfercase is a Klune underdrive followed by a Dana 300 (stock gear ratios in Dana 300). Dana 300 upgraded with 32 spline outputs. Dana 300 to be replaced by Atlas in future.

3. Rebuilt 727 tranny, with B&M shift-kit from IHO, Jeep output shaft/tailhousing

4. Current engine is a tired 304


Ok, onto the engine to replace the 304:

1. Zero deck block w/ Silvolite pistons - Anything available to try to get say 9.5 or 10.0 compression? I'm not concerned with running premium fuel as it's only a trail rig. Even if it's possible, is it worth it? I have flat top pistons.

2. Smooth out oil passages

3. Clean up exhaust side of heads - still researching this. Keeping 392 heads....not putting 345's on....my research shows 392 heads breathe better (not saying much when it comes to IH heads I know, but I'll take it), BBC Valve springs, 3 angle valve job, mill heads just enough to ensure flatness.

4. Balance rotating assembly

5. Stan's Headers

6. Researching any intake manifold cleanup that can be done to enhance torque. Remachine intake if needed to correct as a result of block decking

7. Upgraded ignition

8. Eventually replace carb with FI

Question:

1. Camshaft - Looking at IHOnly's Isky grinds, and am torn between the ISKY-190125-26 and ISKY 190170. Thoughts?

This is my first IH engine build, so still reading all threads I can get a hold of, but figured I'd post up also. Will be ordering parts once block goes to shop and it passes crack check and I see what bore I'm going to wind up with.

Comments?

Thanks....and have a great day everyone...

Rich

[Bill usn-1]

Isky 25/26 cam

Carbs suck on the trail!! If you go EFI then the ignition is already upgraded and the carb won't need tuned. By the time you by a carb that works and the ignition...you could have just done it right the first time.

Headers should only be the tri-y.

I have shown the basic port work for the heads as well as a couple others here.

Most of what you want is in the 304 build thread we talked about earlier.

[FishWagon]

Good point on ignition, and yes sir they do (carbs on trail).

You've convince me to get one of those nice shiney Bill Hamilton kits....

[Mark Ashford]

For a trail pig, not real reason to go exotic with the rebuild. Standard flat-top pistons with standard deck-prep. Cleaning up the oil passages is always good. I've never run BBC valve springs and never had a problem turning 5K+

I'd go deeper on the gears, full manual VB, GOOD shifter. Either a Winters/Art-Carr or modified B&M. Gate style shifter, no ratchets.

Can't comment about the cam-shaft. I'm running a stock on in my 392 I've had for like 10 years. But I want to change it for the near future, just haven't decided what.

392 has plenty of balls for the trail, the closer to "stock" you leave it, the more durable it will be. If you want insane power...... that's what LS's are for