Plenum is all good too bad I'm going with an airgap instead.


























Oh yea, I found out shes bored .030 over as well.

 

Just replace the heads. For under 600 bucks, you can get a pair of NEW heads, with better casting than the stock fellers. (will need to discuss valve springs with them though..... or, if you already have some appropriate to the cam, transfer them to the new heads.)

Going to 1.7 ratio rockers is going to bump your lift to .539..... That's pretty steep. Will your current valve springs take that? Something else to consider.... But, all else being equal, that's a pretty nice cam, don't think you need any more lift, but, full roller rockers would still give you a bit more power.

 

Nice looking engine! 4000 miles, it ought to be clean, and it sure is! When I did my plenum, found out I had carbon buildup pretty bad in my motor (after I bought the truck), I envy your clean engine.

Sucks about your heads though. I'd be tempted to call Clearwater/Odessa and see what they'd charge to get you a set of 1.92 heads with 1 piece valves and the springs you need. They have a wide variety of springs on hand and can hook you up.

 

Based on the cam spec, the valve lift is .506" with 1.6:1 rockers.
.506" / 1.6 * 1.7 = .538"

I believe .545" is the max valve lift before you have piston interference issues.
But .520" is about the limit for retainer/guild clearance.
A competent engine shop familiar with Magnums should be aware of the limits.

 

Stock heads stop flowing at .400" lift. So putting 1.7 rockers on probably won't do anything. Heck even that cam is limited by the stock heads. And if you really needed that much lift I would stick with 1.6 rockers and get a cam with more lift in it. It will save your valve guides and give you better valvetrain geometry.

 

Only cam you can run with the 1.7s without any clearance issues is the cam I have 20-745-9.

 

Hmm that sounds reasonable to be honest. Now I've heard of people recommending these odessa heads? Is that the same as these EQ heads? I'm pretty interested in the EQ heads as they seem like they flow pretty good.
I plan on getting upgraded springs so I'm not too concerned with that as much as clearance.
What do you mean by full roller rockers? Just HS's roller rockers correct?

 

Thank you! I'm very happy with how clean it is, just not so much with the cracked head.
I think I'm definitely going to give them a call.

 

Hmm, I would love for that, that'd be great, but if you look farther down the forum, Redneck_ram states that the 20-745-9 cam with 1.7 is the most you can go without having clearance issues. The 20-745-9 cam has a lift of .480 on int/ex.

 

Thank you!! that chart is extremel useful!! What are these EQ heads? I feel like alot of members here have them on their trucks and seem to flow pretty good.