Rocker selection

South65ss

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Hi there!
Been a while since my last post. I'm getting ready to start finishing this project. Engine is a '75 500 zero decked, .060 over with KB flat top pistons and MTS10 cam and springs. I have milled the heads to intsall adaptor plates for the installation of individual studs and Ford rockers. Question is, with flat top pistons, zero decked block, MTS10 cam and Ford 1.7 rockers, should I expect valve to piston clearance problems? The combustion chambers are pretty big so maybe I'm lucky enough to not have to take the pistons out to make room fot the valves. I still don't have rockers. Any recomendation?
Thanks!
 

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5one9

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You should have no issues with that cam and 120cc heads. Always check anyway with a couple of checking springs or clay.
 

Big Cadoo!

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Hi there!
Been a while since my last post. I'm getting ready to start finishing this project. Engine is a '75 500 zero decked, .060 over with KB flat top pistons and MTS10 cam and springs. I have milled the heads to intsall adaptor plates for the installation of individual studs and Ford rockers. Question is, with flat top pistons, zero decked block, MTS10 cam and Ford 1.7 rockers, should I expect valve to piston clearance problems? The combustion chambers are pretty big so maybe I'm lucky enough to not have to take the pistons out to make room fot the valves. I still don't have rockers. Any recomendation?
Thanks!
Heres the info on rockers.
 

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Big Cadoo!

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Hi there!
Been a while since my last post. I'm getting ready to start finishing this project. Engine is a '75 500 zero decked, .060 over with KB flat top pistons and MTS10 cam and springs. I have milled the heads to intsall adaptor plates for the installation of individual studs and Ford rockers. Question is, with flat top pistons, zero decked block, MTS10 cam and Ford 1.7 rockers, should I expect valve to piston clearance problems? The combustion chambers are pretty big so maybe I'm lucky enough to not have to take the pistons out to make room fot the valves. I still don't have rockers. Any recomendation?
Thanks!
I recently fabbed some rocker stud plates for 76 cad500. 120cc heads. I machined the stock rocker stands till the air tube was .200 wide. The rocker stud plate is 1.300 wide. The plate sits on stock rocker boss locations and the air tube. There is a .375-16 bolt back from each 7/16 factory bolt next to the rocker studs. I drilled the air tubes fron each end 7/16 diameter and installed 7/16 rod fromm each end. The 3/8 bolts tighten thru that and head material. This strengthens the stud locations. God luck with your project and theres people on this site that will gladly tell their Cadillac know how.
 

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South65ss

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Well, I was worried about the air tube so I milled just a little and that screwed the rocker geometry. The rockers I bench tested ran out of slot before full lift. That was some years ago so I might not remember all the details but I do remember I had to mill a little more so the rocker will be further away from the stud and then I could use shorter pushrods.. Guess I will have to take this more seriously if I want to finish this project! I like your idea of filling the air tube. Might take that way.
Thanks guys!
 

Big Cadoo!

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Ive used all the different type rocker assemblies for the bbcad engine. Ive had to mill the stock rocker arm pads in the heads minimum .200 to get proper geometry anytime a camshaft with .600 lift plus was used. Biggest problem was excessive rocker arm down angle at full lift causing pushrod pinch at adjusting cup on rocker arm. Your setup might work with low lift cam. Theres a ball pivot rocker arm for the stud plate method also. SBFord self guided type. When I fabbed the 120 cc cylinder heads I used valves with longer valve stems to get geometry for over .700 lift.
 

Big Cadoo!

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Well, I was worried about the air tube so I milled just a little and that screwed the rocker geometry. The rockers I bench tested ran out of slot before full lift. That was some years ago so I might not remember all the details but I do remember I had to mill a little more so the rocker will be further away from the stud and then I could use shorter pushrods.. Guess I will have to take this more seriously if I want to finish this project! I like your idea of filling the air tube. Might take that way.
Thanks guys!
Pictures of air tube cut away and the 120cc heads I fabricated.
 

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Big Cadoo!

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Really nice setup man! Will work on mine and report results. Thanks for the input!
Also look at moving the rocker arm studs closer to the valve stem. Another way to get more slot clearence is use 76cc head valves in the 120cc head. The 76cc valves are
250 longer. That will set your rocker arm to a steeper angle. The combination of them both will allow for exact geometry. I had to use 5.5 long valves to get enough slot clearence for .600 lift.Larry Kruzik said Time, Money, Patience which do you have more of. If I ever fab another set of heads for rocker studs I will move the studs. Make manila template of rocker arm setup and pin the rocker template pivot point and lay out its sweep.
 
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