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308 heads Vs. Magnum heads
#1527668
11/03/13 12:31 AM
11/03/13 12:31 AM
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Joined: Jan 2003
Posts: 4,576 Sarcoxie, MO, USA
MoPar Jamie
OP
master
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OP
master
Joined: Jan 2003
Posts: 4,576
Sarcoxie, MO, USA
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Hey all,
What are the years that "308" heads appeared on 360s? I know '90-'92 360, but what about '89 360? Found an '89 truck motor locally and was thinking about harvesting them if they are 308s.
Also, I'm wanting to compare them to a Magnum head. Which would be better for a street build?
I have an '86 360 short block and a '78 Motorhome 360 with a dropped valve (bottom end holds great pressure, checked with mechanical gauge).
- MoPar Jamie
1972 Fury III 4dr 1986 D-150 LWB Royal SE
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Re: 308 heads Vs. Magnum heads
[Re: Locomotion]
#1527670
11/03/13 10:53 AM
11/03/13 10:53 AM
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Joined: Jan 2003
Posts: 1,255 Columbus, GA
Michael Ecks
pro stock
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pro stock
Joined: Jan 2003
Posts: 1,255
Columbus, GA
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Start by popping the valve cover and looking for the gigantic pushrod holes. (.66" versus .50" I think) Trucks seem pretty well picked over, pulled mine out a 15 passenger church van. I guessed no one thinks to look in snub nose vans, after I started wrenching in the junkyard I realized its really no one wants to work in snub nose vans. PITA
"The happiness of your life depends upon the quality of your thoughts" ~ Roman Emperor Marcus Aurelius
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Re: 308 heads Vs. Magnum heads
[Re: MoPar Jamie]
#1527671
11/03/13 11:08 AM
11/03/13 11:08 AM
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Joined: Nov 2003
Posts: 36,041 Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,041
Lincoln Nebraska
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The 308 is the best OE iron open chambered SB head & the mag is even better. As you know you need the mag valvetrain related pieces for the conversion & a mag intake or redrill the head intake holes & some have even redrilled the LA intake for vertical holes & used a long bolt with a bushing sliced at an angle on one end. You may need adjustable pushrods and the P5007477 MP pushrods for the conversion may work but I think they are NS1 and they are pretty close in length to the adj MP ones I have. I just posted the measured lengths of all of them the other day for a guy on here but I think I tossed the scrap of paper. Good info on the large pushrod holes so you only have to pop a valve cover to verify. As said reportedly alot of em (OE used mags) have cracks but also reportedly the cracks ain't a dealbreaker & the heads are still useable so the cracks (if present) must not be in a vulnerable area. As you know the mags are closed chambered so the CR will be alot better than using open chambered heads which is another perk. EDIT the better combustion chamber will likely let you lower the total from the SB tried & true 35 down to 31-32 degrees. Check the deck surfaces for flat & good idea on the intake surfaces also. Holler how it works out when you are finished
Last edited by RapidRobert; 11/03/13 11:16 AM.
live every 24 hour block of time like it's your last day on earth
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