I am in the process of gathering parts for a low compression motor home 413-1 short block build. I am not going to touch the bottom end as it only has 20k miles on it. I am undecided and looking on advice on head choices since I can't use the MH heads. Should I go with 516 closed chamber heads to up the compression , or should I run 452 heads for more flow ? This won't be a race engine, more of a cruiser/street engine. Most likely will be topped with a dual plane intake and run a mid range cam backed up with a 727 trans and 3:73 gears out back. Thanks for your help in advance, and please don't recommend rebuilding with higher comp pistons or tossing this engine in favor of a 440.
Low Comp Head Choice
- Thread starter MagicMan
- Start date
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bOb shingler
Well-Known Member
516 would be ok but 915 would be better. even better would be an aluminum head with the smallest chamber you can find.
Woods74
Broke Senior
Toss the engine for a 440 and put higher comp pistons in there! :axe:
In all seriousness, unless you have the gears, you don't need 3.73 with a big block on the street or cruising, unless you like screaming down the highway that is.... 3.23 max.
In all seriousness, unless you have the gears, you don't need 3.73 with a big block on the street or cruising, unless you like screaming down the highway that is.... 3.23 max.
906
69MOPE
Well-Known Member
Mild ported, 3 angle valve job with larger valves using 516's = great flow and more compression
452 heads over 516's. Flow trumps compression.
Gears are already in the car, I figured they would be a bit much for a BB.
I used 906s on mine when I did this. Hardened seats, bigger valves. Cost me $550 with my castings.
On my 440 I used 516s with bigger valves, practically the same as above, just closed chamber. I added 4 degrees advance on my cam for more mechanical compression.
My choice again would be to match port as much as possible, 4 degrees advance and 516/915 heads with big valves. Still $550 at my shop.
On my 440 I used 516s with bigger valves, practically the same as above, just closed chamber. I added 4 degrees advance on my cam for more mechanical compression.
My choice again would be to match port as much as possible, 4 degrees advance and 516/915 heads with big valves. Still $550 at my shop.
69MOPE
Well-Known Member
Mild ported, 3 angle valve job with larger valves using 516's = great flow and more compression
Are those the only two choices, 516 or 452? If so, are you going to leave them unported? Gotta budget for these heads?
Sounds like you have everything else planed out, right?
Nothing is set in stone yet, those are just the two heads that keep showing up while trying to do some research . I would like to keep the budget down if possible , it's a el cheapo kinda project but I understand that sometimes money has to be spent . What is your input ? I was inspired by your low comp 440 build.
txstang84
Well-Known Member
I'm a little curious about this 413...how far down in the hole are the pistons? Are they flat tops? Dished?
68383GTS
Well-Known Member
906,915,or 452's would work.
I think those MH 413s started off with 7.5 to 1 CR. If you dont change your pistons and try to use any open chamber head along with the composite head gasket that usually comes with most gasket sets your CR will be very, very low. 516 or 915 for sure.
moper
Well-Known Member
yup. If you need heads anyway - get closed chambered ones. No more money cost wise and you'll get a little compression boost out of it.
mopar jimmie
Mopar Jimmie
Whatever heads you buy just make sure they dont come from Indy
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