LA Block/Magnum Heads

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66MOPAR77

66MOPAR77

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I'm getting in to a whole new can of worms,
Bought a motor 360 1974 model 27000 Org miles
A set of Magnum heads less than 10,000 miles
Any advice on building this motor
Looking for 9.1 compression around 400-425 hp:burnout:
 
Ma MoPar's create engine, the 360/380 HP, has constantly dyno'd north of 400. They used a 288 intake duration roller cam. I suggest this or a slightly beefier cam. The heads were stock as were the Magnums slugs. A M1 single plain was used along with a 1-3/4 tube header and *I think* 750 carb.

Contact MRL for a roller set up. He has drop in lifters tha are excellent and is wise enough to select a cam for your plan.
 
Does a roller cam in a LA block incure about $1,000 of expense over a flat tappet?

Cam specs are 288/292 .501/.513 lift. 230/234@.050

9:1 compression yields 380+HP 410 TQ
10:1 yields 395+HP 435 TQ
4"stroke 9:1 magnum rt heads returns 435+HP 457tq
 
You know about using AMC lifters , as you will be using push rod oiling with the Magnums....right ?
Different pushrods too.
I am not sure a solid roller is worth the extra expense here either.
If I did go that way , I'd probably lean towards a hyd. roller.
With a solid roller , you will find the limitations of the heads pretty quickly.
I get the impression that you are taking low mile pieces with the intent of running them as is ?
If that is the case , I'd run a nice hydraulic cam ( flat tappet ) and enjoy it.
Getting around 400 h.p. should be doable with this direction.
 
tubtar said:
You know about using AMC lifters , as you will be using push rod oiling with the Magnums....right ?
Different pushrods too.
I am not sure a solid roller is worth the extra expense here either.
If I did go that way , I'd probably lean towards a hyd. roller.
With a solid roller , you will find the limitations of the heads pretty quickly.
I get the impression that you are taking low mile pieces with the intent of running them as is ?
If that is the case , I'd run a nice hydraulic cam ( flat tappet ) and enjoy it.
Getting around 400 h.p. should be doable with this direction.
Click to expand...
That's the object I can't see putting tons of money in a low mileage motor if not needed with a lot of machine work, trout about swapping bearing to be safe and if recommended having the blocked decked with the heads and intake I believe the intake is molar performance dual plane not sure will know a little later this eve
 
Hyd roller the same/more as a solid roller swap.Yes on the AMC lifters. I would go with a mild flat tappet. Stock Magnum heads need 1110 Hughes springs,matching retainers. That good for .530 lift safely. A great move,would be to have the valve guides cut down. It's cheap,usually. Gonna need a cam,230-235@.050 ,about .525-.550 lift. Best of luck.
 
You will find 350-370 ,h.p.,with that manifold.What are you installing this in? Let's start ,there.
 
Idle to 5500 intake. High torque. You'll have to cam it big in order to get 400HP.
 
Cam recommended by com cams with the intake and carb I have
Pt#284 extreme energy flat tappit cam
240-246 .50 110 540-550 lift
What's your thoughts on this cam
I can get cam and lifters for magnum heads for 220.46
2nd choice
230-236 .50 110 520-530
Same price for eather cam
 
The 230-236 cam,I like.Fits the Magnum head flow numbers better. What car,gears and trans,you gonna use?. That has everything to do,with cam choice.EDIT:OOPS!.Definitely the 230-236 cam. Would recommend a 2800-3200 stall converter,and 3:55's out back.Your at the point of needing a RPM air gap.
 
Da bomber hit it! Do that, what he said. Bowl port the heads later.
 
Sorry to but in,but with the XE274h what carb size????????

Thanks.............................PETE.........................
 
We like butts! What combo? I knew you have been building. Watcha got?
 
LA block .060 kb107 stock magnum heads i just got finished porting crosswind Dual plane intake and an eddy 600 and a new XE262h 1.6 comp rollers
 
If 3:23/3:55 gears,spot on. Porting the Crosswind,a good idea.
 
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