magnum heads swap?

[twenty2]

Planning a magnum head swap on an LA engine. A couple of questions.

Can either magnum or LA head gaskets be used? Anything to consider there?

I've read on this forum stock stamped steel magnum rockers have been used but were slightly modified. What's the modification consist of? Is this a do it yourself or does it require a machine shop?

Thanks!

[cageman]

I am pretty sure I used LA head gaskets when I did mine. They never made a 273 magnum. As for rockers, I used all the stock stuff, and I had to get the right length pushrods. It floats the valves at 5400, needs better springs.

[moparallen]

I used the LA gaskets also. The pushrods I used were 7.625 in length. I found the part number in a Mopar Performance catalog. AMC lifters and these pushrods plus the ARP bolts for Magnum Heads. I had to redrill the heads so an LA intake would fit but I did it with a hand drill. The biggest thing is the pushrod clearance. Mine hit the bottom edge of the head at max lift. I used a grinder and cut a notch out. I also made mine where I could adjust them for minimum lash. I love them!
Allen

Allen

[twenty2]

Thanks for info. It's very helpful.

[dirtmopar44]

Here is the best way to do it and have adjustable rockers like a cheby.
get Comp cams guide plate # 4825-8 18bucks, Comp cams rocker studs # 4504-16 (5/16x3/8)65bucks. If you want to use stock magnum rockers get mopar #p4876514. This is the rocker folcrum with 3/8 hole. Cut the bottom of the folcrum off with die grinder. I will post a pic. Or you can use a chebby stock rocker but it will have to be a 1.6 ratio or you will have to grind pushrod tunnel. Get a set of 3/8 polly locks and you have adjustable system. Have been using this system for 2 seasons with zero problems

[moparallen]

Originally Posted by dirtmopar44

Here is the best way to do it and have adjustable rockers like a cheby.
get Comp cams guide plate # 4825-8 18bucks, Comp cams rocker studs # 4504-16 (5/16x3/8)65bucks. If you want to use stock magnum rockers get mopar #p4676514. This is the rocker folcrum with 3/8 hole. Cut the bottom of the folcrum off with die grinder. I will post a pic. Or you can use a chebby stock rocker but it will have to be a 1.6 ratio or you will have to grind pushrod tunnel. Get a set of 3/8 polly locks and you have adjustable system. Have been using this system for 2 seasons with zero problems

That is exactly what I run. Comp sells a kit but I bought the only pieces I wanted. I used a 3 inch cutoff wheel to remove the bottom of my fulcrum. I had 1.6 chevy rockers with polylocks but the tech man did not like the chevy rockers. It is ok for the chevy guys to run a ford rocker but I could not run a chevy. Go figure that out? I guess they are scared of what they dont know? I know I gained some lift and duration by being able to adjust the lash. By my figures I gain about .020 lift at the valve stem.

Allen

[twenty2]

Thanks for the good tips. I can't find the mopar part number p4676514 in the new on-line catalog. Is the number correct? Thanks again.

[dirtmopar44]

Sorry its p4876514 try this site even though it is not listed call him.
http://www.mopartsracing.com/tmc/index.html
Or this site http://www.chicagoconnection.us/inde...Path=1_352_367

[twenty2]

I'm new to stud mount rockers. So when cutting the folcrum with a cutoff wheel they won't be exactly the same height. I'm assuming that's not an issues since we're turning these into adjustable rockers?

[dirtmopar44]

Cut them off just below the rocker arm. The guide plates keep the rocker in line.

[twenty2]

Thanks. I'll get started this weekend.

[deacurt]

Howdy, I had my 273 rebuilt years ago and can't find what cam they used. I'm putting a little 4 barrel so it can breath better. I took out the cam and at the end of it is a stamped 340-S. Does that ring a bell with anyone? Thank you.

[twenty2]

Are there any issues with the right side valve cover filling with oil. Any smoke...

[twenty2]

Any issues with oil collecting the right side valve cover? Any smoke???

[moparallen]

Originally Posted by twenty2

Any issues with oil collecting the right side valve cover? Any smoke???

I can't see from the drivers seat but I have people tell me mine starts smoking after 8 or 9 laps. It can't be too bad, I rarely have to add oil to the engine. My other heads were the same way. Do a search for Avenger29 he had some pics on a post about making a drain to the oil pan.
Allen

[LFD203]

I know this thread is ancient....but...I tried to order the mopar performance rocker arm fulcrums from Chicago Connection and they tell me they have been discontinued. Does anyone have any suggestions or solutions to work around this? I see there are some Ford fulcrums from Summit that look like they could work, but I don't know which ones...if any.

I'm going to be running the variable duration lifters and I have to run factory rockers, so I have to make them adjustable.

[dirtmopar44]

Just use Chevy 1.6 stamped rockers with the stock balls for 3/8 studs. You can also use 1.5 but that will require some grinding on the push rod holes. You have to use guide plates.

[moparallen]

Originally Posted by LFD203

I know this thread is ancient....but...I tried to order the mopar performance rocker arm fulcrums from Chicago Connection and they tell me they have been discontinued. Does anyone have any suggestions or solutions to work around this? I see there are some Ford fulcrums from Summit that look like they could work, but I don't know which ones...if any.

I'm going to be running the variable duration lifters and I have to run factory rockers, so I have to make them adjustable.

I did a search for the part number and called about 8 places before I found mine...I have seen somewhere, maybe on a dakota forum about using viper assemblies. They are supposed to be 1.7 ratio and have a 3/8 fulcrum. This is NOT info I have first hand knowledge of. I would suggest buying 1 assembly to see. There are some viper sites out there. Maybe try visiting them?
Hope this helps...
Allen

[LFD203]

I would run the Chevy rockers, but my rules specify 1.5 rockers, and I have convinced the tech inspector that my truck came with 1.6's. I've already had my cam ground assuming 1.6 rockers.

I live about 5 miles from Summit Racing. I may do some research today to see if any of the Ford fulcrums are a match. I'll take my parts in and do some comparing.

Thanks for the replies, as always..

[dirtmopar44]

Comp cams guide plate # 4825-8 18bucks, Comp cams rocker studs # 4504-16 (5/16x3/8)65bucks Then use a stamped steel chevy 1.6 long slot rockers and 3/8 ball. Use polly locks also for chevy. Then you can adjust just like a chevy. I used this system on my car for years with no problem. tech guy never new the rockers were chevy.

[moparallen]

Originally Posted by LFD203

I would run the Chevy rockers, but my rules specify 1.5 rockers, and I have convinced the tech inspector that my truck came with 1.6's. I've already had my cam ground assuming 1.6 rockers.

I live about 5 miles from Summit Racing. I may do some research today to see if any of the Ford fulcrums are a match. I'll take my parts in and do some comparing.

Thanks for the replies, as always..

Here you go.
Use the comp studs and guideplates Mike (dirtmopar44) listed. That is cheap. Then use a stock magnum rocker, The viper pivot part number is Mopar Part # 05245336. According to the description it uses a .375 bolt. .375 and 3/8 is the same. Then you should be good to go. I found the pivot for less than $3.00 each using google.

Allen

[LFD203]

Awesome!!! Thanks a million. I made some calls today and was pretty much striking out.

[beaudauer]

EQ makes magnum heads for LA engine it uses the LA intake and chevy rockers. also u can use lifters out of a LS chevy motor

[Groundpounder18]

Anyone on here ever use this Magnum rocker setup from Hughes?
http://www.hughesengines.com/Index/p...=&partid=25628

It seems like it would be a pretty solid rig, and after you buy chebby rockers, studs, and stud girdles, it could even be cheaper.

[LFD203]

I ordered the viper fulcrums. They are too large to bed down into the bottom of the stock Magnum 1.6 rocker.....Has anyone ever tried drilling the stock fulcrums to 3/8"?
I was hoping to find a 5/16" rocker stud, but those don't seem to exist. I'm trying to do this as cost effective as I can with as many of the existing parts as possible..

[dirtmopar44]

Just use a chevy 1.6 long slot rocker

[B-Mod Dad]

Groundpounder: We have a set on our EQ's and have only 3 nights on them but no problems. They are nice pieces. took awhile to get right length oil thru pushrods to get rocker arm geometry right. had to get some from Smith Bros. So far our IMCA Stock car had a DNF first night(tranny jumping out of gear) and 2 2nds this past weekend. Right behind leader both nights. 2 more laps Fri. or a caution and we would have won. Had wrong gear and only turned 6500 but motor still stout. Nobody pulls us down the straights. Not even the big cu. in. motors with small carb. IMCA inspector cube checked us Fri. and looked at motor and said we were fine.

[JC]

Yes and it is a pain in the but I broke 2 90 buck end mills. I have thought about tring to order some studs from ARP, what we need is a 2.5 inch stud sae for the head side and fine on the rocker end with a 12 point nut.

[LFD203]

JC, So they're pretty hard then? lol. I'm wondering if they performed ok after being drilled. Any failures?

Dirtmopar, I don't have those....I'm trying to work with the parts I have as much as possible.

[dirtmopar44]

the stock folsrums can be drilled, I gave them to a friend of a friend who has a machine shop he drilled them and said they were a SOB.