flat head hop ups?

I will be rebuilding the flat 4 in my MB very soon, is there some tricks to getting a few more horses out of them..........different cam, header, intake???????????? thanks KimBob

 

There's a few things you can do. Just don't expect too much...

Resurface head/block (I just had them go far enough to clean up the pitting on the block and to get both flat within spec). I can't recall exacts on how far they machined mine (~.020deck and .010and head, I think) but the end result was around 7:1. So far (850miles) no problems. I'd say that less is more here, too much and I hear headgaskets will blow easy and the head will warp sooner. Also, you can't take much off the block before the pistons will hit the head.

Clifford http://www.cliffordperformance.net/ has a grind for the camshaft. On desktop dyno it looks like it should improve power across the board--and only really loose power up beyond 4000rpm (which you can't get to anyway). They increase lift very slightly and actually reduce overlap. In theory, this should increase low end power, but since the L head tops out so early, it actually increases power across the whole power band.

If you run a timing chain arrangement (stock MB) make sure you make it clear to them that your camshaft spins clockwise (opposite all the civillians and F head engines). Very important!

I also bought new lifters at the same time, they go for about 8 each, the cam... can't recall 150? 200? It's a bit...

Clifford also sells a header and a weber carb. I have no idea if they are worthwhile or not.

End result on mine was a bit more power than it had before. Still slows down on hills, still likes to cruise best around 45-50mph with an OD (but it will go faster). Sometimes it cruises at 55-60, but it's heavily dependant on the wind, the road and the position of the sun and moon etc.

Here's a performance L-head (but almost no info).http://clubs.hemmings.com/clubsites/wocv/willywilly/willywilly12.htm#top

I've seen a web site that detailed some old hot rodder tricks for the L-head, but I can't find it. What I remember was radiusing the top of the cylinder that faces the valves, to improve flow into the cylinder. Another one that probably would help (or at least improve life) would be to have the rotating assembly balanced. They also mentioned the stratosphere(?) stratoblaster(?) (forget the name) Willy Willy "performance" heads, among other things. If I find it, I'll post a link.

Last thing, here's my desktop dyno estimate, stock vs modded with the compression bump, .040 bore and cam change. I wouldn't bet a dime on the actual numbers, but the actual change between stock/mod is probably somewhat realistic.



If you have desktop dyno, here's my data files. I basically tweeked and tweeked it until the stock numbers sounded about right, then made the changes.

http://anthill.homeip.net:8080/Jeep/jeep_misc/DD_Lhead.zip

 

This is a flathead v8 but I guess all the principles would apply

 

Offy heads, port and polish, have 'er decked. And then if there isn't enough horses running around for you, super-charge 'er!

Actually, all other things equal, you might be able to turbo charge the flat four. But check with the turbo guys and see where to set the pop off valve (7lbs, 10lbs) to whatever is safe for the little beastie.