Mopar Performance R/T Head Fiasco

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MRL Performance said:
It would be cheaper to run 1.65 or a 1.7 rocker to avoid the pushrod issue than a whole roller setup. But this is an easy fix, just get in there and make the room for the pushrod. A file will work, and it really doesnt take that long. Geat a good new sharp file and it will be done in no time. Elbow grease if free.

As for the old manifold on the new magnum heads, they are going to be a problem. If you are willing to spend the $ for a roller setup, I think you would be better off going with a set of headers instead.
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mrl we have been through this before on another site. used a diegrinder and everything will clear fine they only rub at the top....
 
Correct me if I'm wrong, but the rocker ratio change mentioned is based on the fact that rocker arm ratio's are in the adjuster side of the the rocker, therefore bringing in or shortening that side of the rocker toward the shaft will give more ratio and clear the push rod holes.

fwiw Stock magnums don't really even have push rod holes, more like 1/2'' cut outs.

I would have already run a drill bit through the holes and been driving the car by now.
Those are some REALLY GOOD heads you have there, they make RHS head flow numbers look like they measured through a coffee straw.
 
Fregie, the statement is correct.

A, FYI for those who don't know/understand/missed it;

A higher rocker ratio will move the pushrod in closer to the rocker, away from the contact point in the above pictures.
 
I still dont think that head is located correctly... if you have an original set it on and see if it lines up.
 
buy a carbide cutter and a harbor frieght electric die grinder if you dont have air and just open them up. no big deal. measure them from the intake surface with a caliper or something similar and make them all the same. i just did a head swap on my BB and had to do a lot of grinding for pushrod clearance. i thought of thinner pushrods but they would have done the trick.
 
ham_r_down01 said:
I still dont think that head is located correctly... if you have an original set it on and see if it lines up.
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I know it looks funny but machine shops when milling/decking the block typically do not mill the front/rear end sealing area, so it stands proud like in the pic.

I have 3 blocks all like this, including the current stroker I'm working on.
 
ham_r_down01 said:
I still dont think that head is located correctly... if you have an original set it on and see if it lines up.
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Take a look at the second to last picture here. It's the picture of the lifter value, and the heads are lower there, just like on mine. That is an late 80's roller motor, with 308 heads, not a magnum motor, either.

I have the U heads that cam off the motor still, I will drop one on this weekend and see, but I don't think it is an issue. I don't believe the R/T heads were milled, and even if they were, it wouldn't move the intake face that direction. My bet is that most if not all blocks have that gap, but nobody ever really noticed it.

This weekend, I will set the heads on the block (both of them this time) and set the manifold on the motor to make sure it all clears.

I really don't think that is an issue.
 
TurdFerguson said:
I know it looks funny but machine shops when milling/decking the block typically do not mill the front/rear end sealing area, so it stands proud like in the pic.

I have 3 blocks all like this, including the current stroker I'm working on.
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I would be shocked if my block had been decked, all though it's not impossible. I've either owned this car (and it's original block) or been good friends with whomever did own it when it wasn't mine since 90 or 91. I had it rebuilt in 91, and while I can't be certain it wasn't deck during that process, I really doubt it.
 
340sFastback said:
Its common for people to fab up a plate and sandwitch between head and 340 manifold to get them to seal. Do a search you'll find a thread. Known problem with magnum heads.
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I'd seen it come up, but I thought it had been put to rest that it wasn't an issue with Magnum heads. The stock Magnum heads I checked had enough meat around the ports to make this an non-issue, it's just these R/T heads that seem to have less meat there.

I will do a search, hadn't heard of others using plates. That gives me some hope that it isn't as hair-brained as I thought it sounded at first.

In the end, since I need a cam anyway, I'm going to spring for the Hughes roller lifters and get away from the flat tappet problems. I can see that at first I was maybe over-reacting and the pushrod clearance problem probably isn't that big of a deal, but I wanted a roller cam anyway and it just gives me incentive to go that direction.

After that, I will deal with the exhaust manifold issue.
 
It's a huge deal, man. You really shouldn't have to deal with that. Just drop them off at my house. I don't want you to deal with any more stress caused by those stupid heads.
 
damnimcooltom said:
It's a huge deal, man. You really shouldn't have to deal with that. Just drop them off at my house. I don't want you to deal with any more stress caused by those stupid heads.
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You're right, I don't need the stress. Trade you for a TKO set for an A-Body.

:evil4:
 
dodge freak said:
You didn't get it done yet:newb:
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=;

One of the disadvantages of not having your own garage, you only get one or two days a week to work on your projects.

At the same time, it gives me plenty of time to think about it, rather than jump in and then wish I had stopped to think.

Call it a cop out if you want, but it's given me enough reason to push for the roller cam I wanted anyway. I really don't like where flat tappet cams are headed due to the oil reformulation, and this was enough.

A roller cam is cheaper than (2) flat tappet cams when you have to replace one because you lost a lobe.
 
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