SpeedMaster Head- Rocker Options/Questions

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madhatta360

madhatta360

1973 Duster 340 H-code TX9
FABO Gold Member
Joined
Oct 1, 2022
Messages
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Location
Allentown, PA
Alright fellas, looking for some direction/feedback/expertise on my current situation with my 340 Duster- bought this car in September and going through refreshing up the motor, as always with bought/not built, there is a slight guess work.

Currently, car is a 73' 340 .30 over, Speed Pro Forged pistons- L2316F, J heads, Crane Cam 150062- Flat tappet (Crane Cams 150062 Crane Hydraulic Flat Tappet Camshafts | Summit Racing) and some bottom end work done- to what extent not sure. I reached out to @pittsburghracer to discuss some head work and will be purchasing some Speedmaster heads that will be worked by him. Here are some of my questions below, I appologize in advance, this is my first mopar, so I have been learning A Lot along the way.

1. Can I run stock rockers/rockershafts/pushrods with the Speedmaster heads? I'd like to consider upgrading the rockers/pushrods- whats the best options out there that are compatable with SM heads and simplest to install.

2. I will be using the springs (specs below) from my J heads which match the Crane Cam, will there be any potential issue with that on Speedmaster heads?
outside dia: 1.5"
coil bind: 1"
spring rate: 412lbs/in
inside dia: 1.086

Appreciate the input in advance

-Rookie
 
madhatta360 said:
Alright fellas, looking for some direction/feedback/expertise on my current situation with my 340 Duster- bought this car in September and going through refreshing up the motor, as always with bought/not built, there is a slight guess work.

Currently, car is a 73' 340 .30 over, Speed Pro Forged pistons- L2316F, J heads, Crane Cam 150062- Flat tappet (Crane Cams 150062 Crane Hydraulic Flat Tappet Camshafts | Summit Racing) and some bottom end work done- to what extent not sure. I reached out to @pittsburghracer to discuss some head work and will be purchasing some Speedmaster heads that will be worked by him. Here are some of my questions below, I appologize in advance, this is my first mopar, so I have been learning A Lot along the way.

1. Can I run stock rockers/rockershafts/pushrods with the Speedmaster heads? I'd like to consider upgrading the rockers/pushrods- whats the best options out there that are compatable with SM heads and simplest to install.

2. I will be using the springs (specs below) from my J heads which match the Crane Cam, will there be any potential issue with that on Speedmaster heads?
outside dia: 1.5"
coil bind: 1"
spring rate: 412lbs/in
inside dia: 1.086

Appreciate the input in advance

-Rookie
Click to expand...
Ask pittsburgracer
 
toolmanmike said:
Ask pittsburgracer
Click to expand...
I agree, sounds like he's already has John's attention, and John is doing the heads.
John's been doing this stuff for over 50 years, he knows what works and what doesn't and what's junk and what's not.
 
Expect shortened cam life with 412 lb/in spring rate. Consider Beehive springs.
 
Agree with the above, and talking it over with Pittsburghracer.
And my meager two cents:
Like BP mentioned, any time you've got worked heads, new rockers, who knows what deck height, and whatever gasket thickness you'll use to get the compression ratio that you want; you almost certainly are going to need custom length pushrods.
Don't forget to use steel shims under the springs- high pressure springs can mess up the aluminum seat in a hurry.
 
madhatta360 said:
1. Can I run stock rockers/rockershafts/pushrods with the Speedmaster heads? I'd like to consider upgrading the rockers/pushrods- whats the best options out there that are compatable with SM heads and simplest to install.

2. I will be using the springs (specs below) from my J heads which match the Crane Cam, will there be any potential issue with that on Speedmaster heads?
outside dia: 1.5"
coil bind: 1"
spring rate: 412lbs/in
inside dia: 1.086
Click to expand...
You can run the stock rockers on them, but personally I would upgrade them. Pittsburghracer should be able to advise you on what fits your build/budget - you are in good hands. As others mentioned you will be up for new pushrods in the right length. The speed master heads take a taller spring than the standard head (around 1.8" installed height vs stock 1.65")
 
I advised him to reach out to a few of you guys as I haven’t played around with hydraulic cam builds in well over 30 years. We know the springs need changed out as they are for a hydraulic roller cam but he could keep those for a future build. He’s currently set up for his 484 lift cam so those springs should work for him, I’m assuming his current rockers should work too. Pushrods will be in question and I figured you guys changing over from stock heads to Speedmaster type heads with hydraulic cams have been down this road before.
 
I bought the 1.6 stainless PRW rockers for mine - they seem well made but the engine hasn't been fired yet so don't know how well they will go. Geometry did need a good bit of correction on my setup though. I used smith bros 3/8 pushrods on Mike from B3s recommendation, but that's with a .574" lift solid cam, a hydraulic under .500 lift you would probably get away with the stock rocker gear and certainly wouldn't need the thicker pushrods
 
Question, has anyone used Speedmaster rockers on their heads. If you did were there any issues? Did you need a alignment kit to get a proper sweep?
 
Correct geometry would be the why you could use them or not. Drawbacks are strength and ratio accuracy. The up side is simplicity.

On my SpeedMaster heads with different valves and springs that they come assembled with (I bought mine bare) I ended up using Hughes Rockers. I think I need a thin shim under the stand to dial them in, but that was with my valve heights, cam lift, block deck height and square, gasket thickness and rocker stands to start with.
 
toolmanmike said:
Question, has anyone used Speedmaster rockers on their heads. If you did were there any issues? Did you need a alignment kit to get a proper sweep?
Click to expand...
I have not used them yet, but I bought a set of the Speedmaster 1.5 stainless roller tip rocker arms on their 40% sale a couple years ago. I measured them for a correction kit from B3 Racing and compared them to a set of Comp Ultr Pro Magnum stainless roller tips I also had here. Every way I measured the two are basically identical to my measuring capabilities, so they would require the exact same correction on the same set of heads. Only difference is the materials used.

I have not seen or measured the PRW stainless roller tip rockers to compare these.
 
I wish I could remember the cam lift in my sons car when we first struggled with issues of bending pushrods. A stock or super stock racer suggested lash caps at that lift. Now with .650 solid lifter or roller cams I need a correction kit. No other way around it at high lift.
 
I heard good things about the Hughes engine rocker shaft kit- I’m not going to be running above 4-5k rpm all that often, just going for a hot street setup that’s reliable. I’m all for spending a little extra to get good parts, I’m hesitant on the speedmaster rocker shaft kits, they seem sketchy haha.
 
madhatta360 said:
I heard good things about the Hughes engine rocker shaft kit- I’m not going to be running above 4-5k rpm all that often, just going for a hot street setup that’s reliable. I’m all for spending a little extra to get good parts, I’m hesitant on the speedmaster rocker shaft kits, they seem sketchy haha.
Click to expand...


They have an upper level rocker that I had in my cart three different times during their Black Friday sale. I just don’t have anything that I would use them on or plan to build. I’m loaded up on Harlan Sharp and T&D rockers. I’ll try to find those rockers later.
 
pittsburghracer said:
They have an upper level rocker that I had in my cart three different times during their Black Friday sale. I just don’t have anything that I would use them on or plan to build. I’m loaded up on Harlan Sharp and T&D rockers. I’ll try to find those rockers later.
Click to expand...


Mopar Chrysler SB 318 340 360 Shaft 1.5 DNA® Aluminum Roller Rocker Arms Set

D2424719-39CD-4FD2-AB37-A3F8526B9EFF.jpeg
 
madhatta360 said:
saw them on Amazon definitely an option seems like lots of guys had issues with fitment and the needle bearings coming apart\burning up but again not sure if that was track situation or just street use
Click to expand...


Honestly if it was me with that cam I would try to find an old set of mechanical rockers that we ran years ago. Not so much the 273 rockers as they have those screwy tapered adjusters but an old set of Cranes or possibly another company that offered them. I still see them out there once in awhile. That is unless you are young, have a few extra bucks, and plan on running small blocks for years. Then pony up for Harlan sharps with a 10% off coupon or find a used set and they will last you a lifetime.
 
madhatta360 said:
Alright fellas, looking for some direction/feedback/expertise on my current situation with my 340 Duster- bought this car in September and going through refreshing up the motor, as always with bought/not built, there is a slight guess work.

Currently, car is a 73' 340 .30 over, Speed Pro Forged pistons- L2316F, J heads, Crane Cam 150062- Flat tappet (Crane Cams 150062 Crane Hydraulic Flat Tappet Camshafts | Summit Racing) and some bottom end work done- to what extent not sure. I reached out to @pittsburghracer to discuss some head work and will be purchasing some Speedmaster heads that will be worked by him. Here are some of my questions below, I appologize in advance, this is my first mopar, so I have been learning A Lot along the way.

1. Can I run stock rockers/rockershafts/pushrods with the Speedmaster heads? I'd like to consider upgrading the rockers/pushrods- whats the best options out there that are compatable with SM heads and simplest to install.

2. I will be using the springs (specs below) from my J heads which match the Crane Cam, will there be any potential issue with that on Speedmaster heads?
outside dia: 1.5"
coil bind: 1"
spring rate: 412lbs/in
inside dia: 1.086

Appreciate the input in advance

-Rookie
Click to expand...
Mancini rockers all day!
 
pittsburghracer said:
Now are you recommending their 800.00 rockers or the 500.00 ones. I’m thinking these are the ones you mean.

Hughes Engines Aluminum Rocker Arm, Standard Kit
Click to expand...
Yes those are the ones I was thinking sounds like they cover the oiling/geometry thing that everyone discusses and references B3- again not racing so I’m good with 90% I’ll check out the other link as well. budget not really an issue this s my wedding gift from my fiancé can u believe that haha she did say no more cars or blower for mustang
 
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