Magnum heads on LA block

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bradr440

bradr440

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Sorry if this has been discussed to death but I can't find the answer. I see Hughes says you have to clearance the pushrod tunnels to put Iron Rams on an LA block, so do you have to do this with factory Magnum heads on an LA block? This is an LA block with a hydraulic flat tappet cam. Thanks
 
bradr440 said:
Sorry if this has been discussed to death but I can't find the answer. I see Hughes says you have to clearance the pushrod tunnels to put Iron Rams on an LA block, so do you have to do this with factory Magnum heads on an LA block? This is an LA block with a hydraulic flat tappet cam. Thanks
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magnum blocks use roller lifter that are taller then a flat tappet hydraulic lifter...the taller lifter change the angle of the pushrod going into the head...that is the problem..

since you are going the opposite way....the iron rams aka magnum head will have the pushrod tube in head for a roller lifter....mock it up...put the head on the block with cam and lifter...see if they rub...
 
I put EngineQuest magnum heads (factory replacement head) on an LA block, with flat tappet cam. They offer a magnum head with LA intake manifold bolt pattern and LA style thermostat bypass hose. Everything fit great.
The magnum heads use 1.6 rocker ratio that puts the top of the pushrod closer to the rocker stud/pivot point. I did a little clearance grinding on the heads/pushrod holes with a carbide cutter to clean up casting flash, not because there were any problems. I had no issues with pushrods close to or contacting the heads.

I would do a mock up of your engine with cam, lifters, pushrods, heads/rocker arms/valves with checking springs, and verify clearance. That is what I did, and as said had no problems.
For rocker arms I used CompCam stamped rocker with roller tips. They are cheap and said to be bullet proof. Do what you want of course.
I did need to run small block Ford/Oldsmobile rocker studs so the ARP polylocks would have enough (correct) thread engagement to lock the rocker arm adjustment in place. Hope this helps.
Here is a write up I did on the head build:
http://www.forabodiesonly.com/mopar/showthread.php?t=180777&highlight=enginequest+heads
 
When I built my Magnum headed LA318, I had no interference issues.
 
I'm not 100% on this but i recall reading somewhere that if you use a hyd flat tappet cam in a LA block, you need to use AMC lifters to oil through the pushrods to the rocker gear. (LA engines oil through the block/heads)

Can anyone confirm whether this is true or false?
 
yes..lifter that oil thru the pushrod....AMC...or most of the newer hydraulic lifter oil pushrod also...
 
Ok Thanks guys. I'm going to call comp cams now. I think this is starting to make more sense than putting milled 360 heads on a 318.
 
mancini racing has all you need to do it lifters/ push rods I did this on my 340 with no clearance problems
 
I did it and I had to grind some casting flash off my factory magnum heads...In fact, those heads are in my basement taking up space...with the pushrods, rockers and the R/T springs and retainers. Could probably make you a hell of a deal if you wanted to take a ride up to detroit.

Otherwise it was easy. It ran really nice, it's just my 360 was pretty worn out - and my new 340 has the edelbrocks.
 
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