Guide plates for GT40 heads

[jckkys]

Having problems finding GT40 push rod guide plates. '96 up GT40 heads are drilled and threaded for 5/16" studs that I have. The guide plates need a 5/16" stud hole size and a 5/16" push rod diameter. I can't find any at Jeg's or Summit.

 

[bronconut73]

I am used to seeing 3/8" and 7/16" ...

I think I did 3/8" Comp Cams guide plates....but it was very long ago...
Haven't had the valve covers off in many years.

 

[jckkys]

The GT40 heads are drilled and threaded for 5/16" studs. These studs are available from several manufacturers. Mine are ARP. I called Comp Cams who made the push rods and rocker arms. They have nothing to offer. They even tried to say the drilled and threaded holes couldn't except a 5/16" stud till I listed the available studs on the market. There are guide plates for Dodge magnum heads that have 5/16" studs and 5/16" push rod slots. The spacing is wrong for Ford small blocks tho. I don't see how I could use plates for 3/8" studs and maintain proper alignment.

 

[fishinman78]

I think this is what your are asking for factory pedestal mount rockers to roller rockers

PRODUCT DESCRIPTION
Crane Cams 36655-16 Pedestal Mount to Stud Mount Rocker Arm Conversion Kit for 1979-95 Mustang 5.0L

This rocker arm conversion kit from Crane allow you to convert engines with pedestal-mount rocker arms into adjustable-type valvetrains, without machine work or cylinder head removal. It allows the use of 3/8" stud mount rocker arms. These kits allow standard pushrods to be retained, in most instances, as the guideplate uses a special composite insert that prevents metal-to-metal contact. Each of these kits includes guideplates, guideplate inserts, studs, a stud installation nut, and instructions. These kits are intended for mild performance applications using hydraulic lifter or hydraulic roller cams. They're not recommended for competition use.

 

[jckkys]

78, I think that will work. Thanks. I see these are also good for Dodge Magnums that are the only other heads that use 5/16" studs. The spacing is different than Ford small blocks by about 1/16", but the holes on the Crane kit are elongated to work with both engines. Oddly Summit didn't seem to know about the Crane kit, when I called them. I'll chew them out tomorrow.

 

[Broncobowsher]

The GT40s don't use studs. They use a bolt down pedestal style rocker. The pedestal has a sled to it that aligns the rocker and you don't use a guideplate. You are trying to use the wrong style valvetrain for the head.

If you really have to run early style valve train on a new style head, something I strongly don't recommend, the bolt holes will need enlarging for proper sized studs. 5/16 works for the pedestal since the structure to hold the rocker in place comes from the pedestal, the bolt just holds it in place. But studs mounted rockers have all the side loading on the stud itself. Thus the need to be beefier as they are the structure and the holding device together. 3/8 is what stock was, any decent aftermarket will be 7/16"

 

[1badd73]

https://www.rockauto.com/en/parts/enginetech,ERK889,rocker+arm,5656

I just bought these for my GT40 heads that Im putting in my sons Mustang. It's the correct style like Broncobowsher stated.

 

[WheelHorse]

I think this is what your are asking for factory pedestal mount rockers to roller rockers

PRODUCT DESCRIPTION
Crane Cams 36655-16 Pedestal Mount to Stud Mount Rocker Arm Conversion Kit for 1979-95 Mustang 5.0L

That's the kit I used on my E7's. I used the factory rocker arms from the Bronco.

 

[jckkys]

The GT40 heads are drilled and threaded. There are rocker arm studs that screw into those threaded holes. What Ford used those holes for is irrelevant. The conversion kit cited by fishinman78 works by using those holes for studs. That's an excellent system enabling use the Ford head design to add adjustable rocker arms without the need for machining those same heads. The valve train Ford used on almost all their heads need different parts to enable the installation of adjustable rocker arms. Who cares what valve train parts they used originally? Adjustable rockers are an advantage on any engine. They also cost more than the non adjustable type. So Ford rarely made engines with an adjustable valve train and almost all those had solid lifters. Are we to believe only original type valve train parts are OK. I guess an improved cam profile would also be incorrect according to Broncobowsher. That's BS.

 

[Broncobowsher]

OK, so Crane makes this oddball kit to retrofit old style rocker arms onto new heads. It looks like the kit comes complete with guides as well. So what is the problem? You have just the studs but not the complete kit? Sounds like you need the Crane kit but without the studs.

 

[jckkys]

The Crane kit was made to use non hardened push rods. Kind of a silly goal if an owner wants to upgrade the valve train. I'm running adjustable Comp Cams magnum roller tipped rockers and hardened push rods. So I'm also using hardened guide plates. Like most anyone who wants adjustable roller rockers. The problem is; of the many manufacturers who make guide plates for Ford small blocks, non make them for 5/16" studs. That make no sense when you consider several do make 5/16" studs that work on unmodified GT40 heads.

 

[walls]

Why go through all that time , money and effort to end up with heads that make about 7hp more that stock heads. Now if you put a camshaft with a decent profile in the motor that requires some valve spring pressure you are going to rip that 5/16 hardware right out of the casting. They make some nice aluminum victor jr or afr heads these days that are fair priced and come ready to bolt on with nice size studs, guide plates and valve springs for a good size camshaft. Nice and easy , affordable and end up making some power you are actually going to feel when you are finished bolting them on.

 

[Broncobowsher]

Why go through all that time , money and effort to end up with heads that make about 7hp more that stock heads. Now if you put a camshaft with a decent profile in the motor that requires some valve spring pressure you are going to rip that 5/16 hardware right out of the casting. They make some nice aluminum victor jr or afr heads these days that are fair priced and come ready to bolt on with nice size studs, guide plates and valve springs for a good size camshaft. Nice and easy , affordable and end up making some power you are actually going to feel when you are finished bolting them on.

I'm with you on that. But I already got slammed once in this thread. At this point I'll just step back and wait for the train wreck.

 

[jckkys]

I've built the engine for low end torque, IE 1500-3500 RPM. Race car engines that wind up to 7500, are poor choice in a 4x4 TRUCK used for daily driving and off roading. So a "good sized cam" for my needs has about 200 degrees of duration at .050". The engineers at Comp Cams had no problem understanding the concept, and recommending my combination of components.

 

[walls]

I'm with you on that. But I already got slammed once in this thread. At this point I'll just step back and wait for the train wreck.

More like valve train wreck....

 

[jckkys]

I'd like Mr. Walls to clarify. Why would a low RPM torque engine be a valve train wreck? . Apparently the hod rod mentality demands that high RPM/horse power has to be the only possible goal in engine building. Sad.

 

[bmc69]

I've used that Crane stud conversion kit on a number of Cleveland builds and have yet to have the first problem with one. That said..I do NOT use that kit on higher RPM/higher valve lift "race" engine builds..the studs would surely pull out or snap off.

 

[walls]

I'd like Mr. Walls to clarify. Why would a low RPM torque engine be a valve train wreck? . Apparently the hod rod mentality demands that high RPM/horse power has to be the only possible goal in engine building. Sad.

Just giving my opinion to someone who put up a post about "having problems" finding parts to piece together a set of heads that when all said and done are not worth the time, effort and money you put into them. Been there done that. You wouldn't be doing any of this unless you are looking to make more power and have a better flowing cylinder head. That being said you can order a nice set of aluminum heads that are affordable ,make power and have beefy studs, guide plates, valve springs and so on. When the day comes and you want to bury the pedal in the rug you wont have it in the back of your head that the motor may come apart because of the marginal pieces and parts you "had trouble " finding to put your top end together.

 

[jckkys]

Your opinion only prioritizes high RPM HP. My priority is low RPM torque. High flow aluminum heads, like long duration cams, hurt low RPM operation. So they would be a real waist of time and money, for me.

 

[Broncobowsher]

If all you want is a simple low RPM engine, why not just use simple stock valve train design?