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Magnum heads and timing cover on a LA block?

Posted By: Guitar Jones

Magnum heads and timing cover on a LA block? - 03/07/20 11:18 PM

So I'm thinking I want to just put the Magnum heads, timing cover and front accessories on my LA 360 and keep the flat tappet cam I have. I know I will need the Edelbrock Magnum air gap intake and different pushrods but am I missing anything else? It already has an electric fuel pump so that isn't an issue. Does anyone know what off the shelf pushrods will be needed?
Posted By: fourgearsavoy

Re: Magnum heads and timing cover on a LA block? - 03/08/20 01:15 AM

It will probably make a difference if you are using the stock stamped units or Chevy rockers. twocents
Gus beer
Posted By: 68shifter

Re: Magnum heads and timing cover on a LA block? - 03/08/20 01:34 AM

Have or drill your heads for both intake patterns. Makes life way easier.
Posted By: Dave_J

Re: Magnum heads and timing cover on a LA block? - 03/08/20 02:05 AM

You will also need the AMC 904 lifters with the oil hole for the hollow pushrods.

My son did this hybred on a 1978 318 block. He used stock LA front but the Magnum heads he had the intake bolt holes dual drilled. I can not remember what hollow pushrods he ordered.
Posted By: gregsdart

Re: Magnum heads and timing cover on a LA block? - 03/08/20 02:12 AM

You need AMC oil through the pushrod lifters, and coresponding pushrods of the right length. Your best bet is to buy EQ 318 b magnum replacement castings, which have the LA bolt pattern. Use Olds rocker studs if you want to run sbc 1.6 rockers. If you go with stock rockers the stock parts are ok. If you go sbc rockers Comp makes guide plates, but be sure and check for proper pushrod clearance. WHEN BOLTED TO THE HEADS . Mine came slightly warped and i had to file ALL of them. I am not sure but you might need to block the oil passages in the block deck surface that feed LA head rocker shafts.
The 318b heads flow very well with a little bowl work. The spring pockets can be cut .100 deeper to allow higher lift cams. These 318b heads make better power and tolerate more compression than LA castings i believe. I made 504 hp with 318b mildly worked(bowls only 2.02 int 1.60 ex) on a 408.
Posted By: Guitar Jones

Re: Magnum heads and timing cover on a LA block? - 03/08/20 07:22 AM

Yeah I knew about the lifters, most all the lifters that come with aftermarket cams have pushrod oiling. I don't want to run any LA intakes as the water neck is in the way of the A/C compressor. I had planned on using the stock rockers for now.
Posted By: dvw

Re: Magnum heads and timing cover on a LA block? - 03/08/20 12:34 PM

I'm doing a magnum using 1968 318 LA front cover, brackets, pulleys, valve covers, fuel pump, and mounts. The intake to water pump neck required a 45 degree to 1" pipe fitting for the the by pass hose. The LA throttle bracket fit after bending the mounting tabs for the Magnum intake bolt angle. As stated lifters need pushrod oil provision. LA valve cover fits the Magnum head. Right side motor mount needed 1 hole drilled. Left side motor mount required a spacer.
Doug
Posted By: Guitar Jones

Re: Magnum heads and timing cover on a LA block? - 03/08/20 01:06 PM

I guess I should have stated the purpose of this is to get the Magnum front accessories on to the LA engine, not so much a performance increase although that would be a bonus.
Posted By: 540challenger

Re: Magnum heads and timing cover on a LA block? - 03/08/20 01:17 PM

Also u will need and electric fuel pump, magnum timing cover doesn't have the provision for mech.
Posted By: RapidRobert

Re: Magnum heads and timing cover on a LA block? - 03/08/20 02:30 PM

buy or make a length checking pushrod then read the B3 raceing utube vid on "rocker arm geometry". He's the guru on this.
Posted By: Guitar Jones

Re: Magnum heads and timing cover on a LA block? - 03/08/20 06:51 PM

The truck already has an electric fuel pump. I don't think the LA heads will work even with redrilling the intake bolt holes as the Magnum belt tensioner bolts to the heads and it looks different than the pattern on the LA heads, thus the reason to swap on the Magnum heads. The Edelbrock intake is the only one I know of that is still available that has the offset water outlet to allow use of the Magnum front accessories so I guess what I need to know is what pushrod to use. I want to keep the stock rockers and all so I'm not interested in doing a race setup rocker arm geometry. This isn't a race car or even a high performance car, it's a 4X4 truck that will not see 5800 very often if it all.
Posted By: mgoblue9798

Re: Magnum heads and timing cover on a LA block? - 03/08/20 07:00 PM

https://www.forabodiesonly.com/mopar/threads/magnum-head-conversion-pushrods.391022/
Posted By: Guitar Jones

Re: Magnum heads and timing cover on a LA block? - 03/08/20 10:27 PM

Ok, thanks, that helps.
Posted By: Jerry

Re: Magnum heads and timing cover on a LA block? - 03/08/20 10:51 PM

we just released a small block serpentine belt drive kit that uses the magnum accessories on an LA engine. if that's the only reason your doing this swap, i'm sure our kit is way cheaper and easier than tearing down the whole engine...

here is a pic

Attached picture small block serp kit.jpg
Posted By: Guitar Jones

Re: Magnum heads and timing cover on a LA block? - 03/09/20 04:24 AM

Looks nice. Can you provide more info please? I figure $400 for the intake, $100 for pushrods and about $100 for gaskets. I already have a complete 5.2 so I don't need to buy heads or rockers for the swap. How much is your kit? It looks like it may need some custom A/C hoses as the compressor is moved to the side.
Posted By: Jerry

Re: Magnum heads and timing cover on a LA block? - 03/10/20 12:50 PM

the kits start at $650 and come complete with billet pulleys at around 1k depending on the options you want with the kit. you can use the magnum pulleys with our kit and the alternator etc. you will need some custom ac hoses but would most likely need them even with a straight up magnum conversion as well. i'll try and get pics of the final posted today.
Posted By: Guitar Jones

Re: Magnum heads and timing cover on a LA block? - 03/10/20 05:19 PM

OK, thanks, looking forward to seeing it.
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