Magnum cylinder heads to LA block
- Thread starter 91dowdge
- Start date
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Magnum heads will directly bolt on. You'll be limited to magnum style manifold.
Never had a carb. The "beer keg" injected manifold only. Aftermarket carb intakes are available.
plymouth67
It be a lot cooler if you did...
You also will need to measure for pushrods and, buy oil through pushrods. Magnum engines use a pedestal style rocker arm and oil through the pushrods like a GM. LA motors oil through the shaft as they use shaft mounted rocker arms. Also depending how old your lifters are they also may not have an oiling hole in the seat of the lifter. Years ago most cam manufacturers went to an AMC style lifter as they are the same dimensionally as a small block Mopar but have the oiling hole. They figured there was no need to make 2 style lifters.
EQ has Magnum heads with LA intake bolt style. I hear you can run LA valve covers too.
I’m considering this for a future build where I want a painted cast iron head. I don’t want two blocks of aluminum on this certain engine. I know mopar dudes could tell but others won’t notice. Great way to get closed chamber heads and fly under the radar.
Maybe a relevant question to the op but do LA front accessories bolt on?
I’m considering this for a future build where I want a painted cast iron head. I don’t want two blocks of aluminum on this certain engine. I know mopar dudes could tell but others won’t notice. Great way to get closed chamber heads and fly under the radar.
Maybe a relevant question to the op but do LA front accessories bolt on?
plymouth67
It be a lot cooler if you did...
Yes, LA accessory bolt up and LA valve covers bolt right. My Duster has this combination and it's easy as pie.
Any ideas on what a set of EQ LA/Magnum heads would for a low compression era 340? I figure the closed chamber would do a lot for it. Cam is 224/224 @.050", 3.21 rear gear.
My compression is too low for that cam and would rather replace the heads than getting into the trap of changing pistons like the ol' "while I'm in there" attitude. I'd end up building a whole new engine.
My compression is too low for that cam and would rather replace the heads than getting into the trap of changing pistons like the ol' "while I'm in there" attitude. I'd end up building a whole new engine.
The Magnum heads will bolt right on. You can use a LA style intake but you have to drill new bolt holes in it that convert it to the magnum bolt pattern. There is a template for it that is available on the internet. The LA accessories bolt right on. Stick with the Magnum valve covers, a little more clearance I believe. You will need new lifters and pushrods that allow oil to pass through to the rockers. My previous engine was a LA 360 with Magnum heads and worked very well with a CompCams 268 hydraulic flat tappet cam and a 650 Demon carb.
Jack
I could be wrong but don't the 340 pistons stick out of the hole which would make it so Magnum heads would not work?
Jack
TT5.9mag
Two atmospheres are better than one
He said “low compression 340” which probably means later than 72 and no pistons above deck.
TT5.9mag
Two atmospheres are better than one
You have the LA engine out of the truck right? I think that’s what you said in your other thread. Just get the whole magnum engine and drop it in. It’s a direct bolt in. Put a carb intake on it, your accessories and smile for miles.
I agree, doing it with the Magnum engine gives you the roller cam option built in.
Jack
It is a low compression 340. 340's went to a cast crank and low compression pistons. My car is a 73 340 so believed to be somewhere in the low 8's for compression. Looking at the internet it says adding a Magnum head (~ 62 cc) will provide up to 1 full point of compression over the ~72cc LA head. Brings up cylinder pressure and adds compression. This was my catalyst for looking into the Mag head on my 340. It's very stock appearing other than the LD340. With the 224 cam and low cylinder pressure it is underwhelming. The cam is a SFT and if I were to go Magnum heads I would probably feel inclined to do a HR cam and get some retrofit lifters. Future plans call for a 3.09 gearset for the 4-speed so paired with more cylinder pressure driving would be a lot more fun. It has a 3.21 rear gear that I like and I'm thinking the whole combo would be more optimized.
I looked closely at my LA cylinder head and instead of 180 intake valve I have 195 valves like a magnum. I also have oil passages through my push rods and my roller lifters. I know that 90s 360LAs had roller lifter but I didn't know they had oil passages. the weird part is that the 360 oil passages through the cylinder heads are still there.
Does your block have a set screw in the head oiling hole? Can oil be restricted by using a Magnum head gasket?
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