Separate names with a comma.
440 heads are 69 or 70
383 is 65
Will they work?
All info is good info thanks ahead of time.
Yes, your compression will drop, if it is a 2 bbl engine it will be very low.
Starting in '68 big block heads switched from being closed chamber to open chamber and 383 & 440 engines started using the same heads. I don't know about '65's but in '66 - '67' 383 heads used a smaller exhaust valve size vs. the 440 engines.
If you are rebuilding your engine you should go with the '69 - '70 heads, which are referred to as 906 heads, just order the right pistons to use with the 906 heads. If you are just looking to swap heads with no other changes, personally, I would not do it since, as noted above, the compression ratio will drop significantly resulting in a decrease in power.
I believe the "383 Magnum" ran 440 "Magnum" heads stock. I've got the 906 heads with that Commando short block. Mind you, my current running 383 is a 1966 2-barrel one with 516 heads and it actually runs very nicely, given what it is. Still, if/when I rebuild the 400, while I plan to use the crank from a 383, I now am persuaded the 452 heads that came with it will stay with it, with some refurbishing. Now if I came by some 915 heads, that might make really interesting things possible for a 400 block....
Not all 915s came with bigger exhaust valves, just the ones used on high performance applications, otherwise they’re just like the 516s.
I had a set of small valve 915s rebuilt with the bigger exhaust valves for my Imp.
Yeah, I saw that the 1st yr for 915s made them valve size identical to the 516s. Pity that all the INTAKE valves topped out at 2.08 ". I reckon anything larger would require canted angles, which drive up CO$T, contrary to the very motive for designing and building the wedge engines.
I did that and some porting work to my 516's, really woke things up!
Thx! So 516s CAN be intelligently modified into something a bit peppy eh? Thought so. This turquoise 383 in Mathilda has run very nicely since I just got it a decent dizzie and carb. I suspect its been opened up topside ONCE but is otherwise still pretty much what rolled off the line 54 yrs ago. Letting the motor rid itself of spent gases without unneeded effort is one of the fundamental things to making efficient power. THAT is what I want out of my engines: efficiency.
ran 75 mh heads on my 65 880 rag 383 , auto , no issues . even ran this intake with a solid cam n headers . under the hood .
My experience has been the improved flow of a 906/452/346 head gives better performance than a 516 stock for stock. Fast68plymouth on moparts proceed what stock, valve job, and a little porting does to all of them 15 yrs ago. In the tech archive.
516's can have a 78-80cc chamber and the others 88-90. I have a set of ported 516's with a decent deck mill to get them to 72cc
I almost certainly will stick w the 452 heads I got with my RV 400 when I rebuild it. Given how well my current plant runs, I strongly suspect a 3 angle grind and hardened seats on my 516 heads. I wouldn't be running those corn squeezins without SOME little mods on those 50+ yr old heads. So long as it runs well, I'm not about to meddle past the head gaskets. I've had the valve covers off to look over a few basics, (like the casting numbers, rocker arms, pushrods, clearances between them and such) and that satisfied for the present. Tilly fires on all 8, and running 10w-30 Rotella T5 made the one noisy lifter quiet down and play nice w the rest. If it ain't broke, don't fuck it up.
Its an 4bbl motor. Both are
My 440 heads came off a Hp motor. They do have the bigger exhaust valve
It needs to be rebuild badly. I have alot of blow by. But still runs.
Regardless of what others badmouth about the 516's and 915 heads, lots of people will use them [esp. racers] with the bigger exhaust valve anad a port job because they are a smaller combustion chamber and raises compression. That, or they swap to aluminum to save weight!
Moparts on the Web - Main Index
don't take my word for it.
stock, there's a difference. A real mopar engine builder who understands the heads can make any of them work, at a cost. Harder to find these days it seems, but serviceable 906's are the best buy for good flow with a street sized cam.
When I finally take the motor out and get both casting numbers I will repost this
DO rebuild SOON then, if you're "foggin skeeters" w that motor! Mine still runs TIGHT, scarcely leaking save on plugs #1 & 3, for which I thank the Lord. Have you done a thorough compression check? Both dry and wet? This will help prepare your budget, knowing somewhat of how much machine shop time you'll need to hire.
Hmm, good to keep in mind. I might have serviceable 906s...... Don't know how far onto that road I care to go though. They'll need the valve seats hardened at the least.