I have a 1979 225 in a d100 and a 1980 225 in a ram trying to figure out which one else will be better to build both run but looking to get some extra torque how far can I bore it before the walls get to thin

_________________
Learn something every day...even if it's a different way to do something you already know

0.060" is no problem at all. Some people have gone over 0.100", even up to 0.200", but on earlier blocks. I would do 0.060", most likely. You will not gain much power from this alone, but it can help unshroud the valves if you use bigger valves in the head.

Lou

_________________
Home of Slant6-powered fun machines since 1988

My philosophy is "When in doubt, go with the oldest block and newest head" when dealing with a slant six. That's my $0.02 on it. You really won't gain much performance boring a slant out as far as it will go. It's better to bore them the least amount possible so you can rebuild them a couple more times.

_________________
If it was easy, everybody would be doing it.

As has already been mentioned, nothing much is gained by overboring a slant six. I second the arguments that ou should overbore only enough to clean up the bore and/or unshroud oversize valves. .060 is plenty overbore for oversize valves.

_________________
Casually looking for a Clifford hyperpak intake for cheap.

Thanks guys I think I'm gonna go .020 or .030 over and mill the head like .090 then over sized valves and stronger Springs

_________________
Learn something every day...even if it's a different way to do something you already know

Instead of picking random numbers, you should do the math to calculate the dynamic compression ratio to find out exactly how much the head should be milled. You will be better off in the long run.

_________________
Casually looking for a Clifford hyperpak intake for cheap.

Correct.
This is also correct.

If you are putting together a torque build with a short cam, you need to make sure you have your measurements and math down... nothing chaps worse than not having enough compression to support the cam, or too much and no matter what you do, it rattles until it knocks a hole in the piston.

If you are going for a streetable torque build... and using an RV style cam like the OCG 819, you need to make sure you have min 9:1, but no more than say 9.3:1 to properly support the upgrade.

Also to make more torque in a useable range, you have to advance the cam when you degree it in... but... there is a limit... here again, you will need your measurements so you can run the DCR calculator and make sure you haven't over advanced it...

Also since these cams have a bit more lift over stock, doing head work... cleaning up the ports and matching the runners will help make gains as well...

After that, a little more carb and exhaust makes the next bump...

Better rear ratio also helps get things motivated better...

Well, everybody has missed this so far, the very first question You need
to answer to Yourself & ourselves is..............what fuel do You want to
HAVE to run. If You have no problem always fillin' 'er up w/premium
then there are many things to enhance torque & efficiency. If You'd like
to get by day to day on regular, You'll have to play it conservative.