Magnum replacement heads

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The LAX flow pretty well, but you’ll need the LA rocker gear and intake.

They’re pretty heavy too.

I’ve only had one set here, and I don’t recall what the guide sizing situation was like.

Ootb on a 4.00 bore with 1.92/1.62 valves:

Lift—— in/ex
.100 — 65/53
.200 —118/104
.300 —172/145
.400 —217/167
.500 —245/174
.600 —253/176
 
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RAMM said:
I know, didnt want to add confusion with the metric spelling. J.Rob
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Every time I see one of the old AMC pick-up trucks I get a bit of a chuckle...

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PRH said:
The LAX flow pretty well, but you’ll need the LA rocker gear and intake.

They’re pretty heavy too.

I’ve only had one set here, and I don’t recall what the guide sizing situation was like.

Ootb on a 4.00 bore with 1.92/1.62 valves:

Lift—— in/ex
.100 — 65/53
.200 —118/104
.300 —172/145
.400 —217/167
.500 —245/174
.600 —253/176
Click to expand...
"They're pretty heavy too." HAH! They are like lugging around an iron FE Ford intake manifold!

Porting them I've found out you need to be careful with the #2/#7 exhaust port as the wall is somewhat thin in one spot. And the pushrod hole was drilled real close to the port wall in some ports, so the port wall was not even .060" thick sometimes.

I like the LAX head because it still has the un-machined stud mount rocker pedestals and you can set the rocker stud anywhere you want (i.e. make it a Magnum head).

We were getting almost 310 cfm but the cross sectional area at the pushrod pinch chokes the higher rpm power potential in a stroker unless you plug the pushrod hole and move it over so you can open the pinch. Because of that we found the pump gas 424/360 running out of air and stalling at 620 or so horsepower @ 6,300 rpm.

Early in the production run (2010) you could buy the LAX with no intake pushrod hole and punch them in there where ever you wished.
 
IQ52 said:
"They're pretty heavy too." HAH! They are like lugging around an iron FE Ford intake manifold!

Porting them I've found out you need to be careful with the #2/#7 exhaust port as the wall is somewhat thin in one spot. And the pushrod hole was drilled real close to the port wall in some ports, so the port wall was not even .060" thick sometimes.

I like the LAX head because it still has the un-machined stud mount rocker pedestals and you can set the rocker stud anywhere you want (i.e. make it a Magnum head).

We were getting almost 310 cfm but the cross sectional area at the pushrod pinch chokes the higher rpm power potential in a stroker unless you plug the pushrod hole and move it over so you can open the pinch. Because of that we found the pump gas 424/360 running out of air and stalling at 620 or so horsepower @ 6,300 rpm.

Early in the production run (2010) you could buy the LAX with no intake pushrod hole and punch them in there where ever you wished.
Click to expand...

^^^^^This is valuable info--Very rare these days. J.Rob
 
I think he is leaning to the mopar performance R/T heads at this point. When I get both sets here, I'll update the plan. And again, THANK you guys for the input and advice!
 
Well, he brought me a set of indy ma-x heads, and a set of mopar performance r/t heads. Looking them over, I think the indys are what we will use for now, as the overall condition it pretty good. The have had some minor bowl blending, but otherwise stock. I think a good multi angle valve job, unshrouding the top cut, and a little deeper bowl blend is all they need. Will post pictures if anyone is interested
 
replicaracer43 said:
Well, he brought me a set of indy ma-x heads, and a set of mopar performance r/t heads. Looking them over, I think the indys are what we will use for now, as the overall condition it pretty good. The have had some minor bowl blending, but otherwise stock. I think a good multi angle valve job, unshrouding the top cut, and a little deeper bowl blend is all they need. Will post pictures if anyone is interested
Click to expand...
Always like pictures. Post some, please.
 
Started with just taking them apart, washing them off, a general look-over. Nothing really remarkable, bowl work looks to my NON professional eye, to be pretty nicely done, valve job pretty run of the mill. No real "porting" which I think is a plus.
20200421_150855.jpg
20200421_150929.jpg
 
I think all I will do, is a relief top cut, a 3 angle valve job with the Goodson 3D cutter, back cut the valves, and blend the bottom cut into the bowl. Should be a pretty decent street performance deal.
 
guides ok do first if necessary
cut the guides for viton seals
put a cross hatch on the stems with some fine wet and dry i USE A SUNNEN STEM HONE
if you have the tooling ask PRH or seat cut, next cut slightly narrower, then a couple more till your plunge cut but the next do not have to be wide
just slightly better to split the 45 to 60 in half and same going to the top cut
If I am not current PRH please straighten me out
having used the Serdi makes me lazy
 
There allready set up for positive seals, and guides are nice on these, no work needed there. I appreciate the input! I'll have to re read the comments about seat angles to make sense of them...
 
Interesting, cleaning up and inspecting the valves, the exhaust has a roundish profile around the margin, and it appears they are not cut at 45° on the seat, it looks more like 35° or so. Haven't seen that, but again, I'm a novice soooo
20200422_104953.jpg
20200422_105006.jpg
 
prh could say it better but there are better valve jobs than the old 30 45 60
one later rule of thum was no more than 7.5 difference in angles
wich could be done with stones
seat width depend on your usage but not race narrow on the street 9for me0
sould be threads on this or try speedtalo but a lot of info is race oriented
 
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