Can Magnum sb head guides be drilled out to 11/32" ?

Is 11/32 larger than 8mm? I think so. Could this be done in order to use a chevy valve, for more common locks and retainers?

How hard would it be? $$??

Thanks.

I have a friend with some odd heads direct from mopar, they have a part number that was never released. They have 11/32 guids in a magnum casting. He keeps calling them R/Ts but they are just a magnum head with bigger guides.

This is actually a popular mod, run a chevy valve plus .100 and there are tons of springs and retainers. I just wish someone made a plus .100 valve for magnum heads, how hard would that be? They would be lighter and less friction and could run LS1 springs with there behive advantages and lighter retainers. It would be a big help especially for flat tappet cam guys, they could run a little less spring preasure and still have good control of the valve.

Just think of all the guys running EQs, Magnums, R/Ts, Pro-Toplines, aluminum magnums.... that could use 2.02 valves.

What are the stock mag head valve dimensions?

1.920in 1.620ex?
8mm stem
______ Length?


Are OOTB EQ's worth more power over stock mag castings?

Who has the best deal on them?

Thanks HRDave

I think the lengths are 4.90 and 4.95 but not %100 sure.

EQs will make about %3-%5 more power OOTB and have hardened ex seat inserts. They can also make more max power after porting.

Clearwatercylinderhead on flea-bay is the cheapest I have found. They sell bare ones, they sell assembled like stock, one like stock but with LA intake bolt holes, and one with 2.02 valves and good springs and retainers. I think they call them iron rams and heavy dutys. I think there store name is HeadsByCCH I have bought stuff from them and they do real good getting it shipped fast and not mixin up the orders or anything.

If you are going to go to the trouble of enlarging the guide ID's it is worth considering a sodium filled exhaust valve and matching the new guide internal diameter to it.

The Ford 427 sodium filled exhaust valve is close in size to the Magnum but thicker stemmed, but a more modern valve design would be preferable in terms of reliability

Please keep us posted on what you end up doing

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I think the lengths are 4.90 and 4.95 but not %100 sure.

EQs will make about %3-%5 more power OOTB and have hardened ex seat inserts. They can also make more max power after porting.

Clearwatercylinderhead on flea-bay is the cheapest I have found. They sell bare ones, they sell assembled like stock, one like stock but with LA intake bolt holes, and one with 2.02 valves and good springs and retainers. I think they call them iron rams and heavy dutys. I think there store name is HeadsByCCH I have bought stuff from them and they do real good getting it shipped fast and not mixin up the orders or anything.

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Carolina Machine Engines is cheaper (http://www.cmengines.com/)

I emailed them for a quote, they quoted me $325 each for engienquest 318B's With new OEM valves, keepers, and seals and GM3100 springs/retainers and $425 for them with chev +.1" long valves and springs/retainers good for a hydraulic roller up to .55" lift