Mopar P4876850 Magnum conversion throttle/kickdown bracket: Usable or MP's baloney?
I'm splitting this off from my Maglam (Lagnum?) conversion thread, as it is about time the Mopar P4876850 conversion bracket gets some attention (seeing as there isn't a single discussion that I can find about its use on Google) to see whether it is actually possible to get kickdown working on this thing without welding - or whether it's another dead-end Mopar Performance part.
Until I received mine in the mail yesterday, all I knew of this bracket was this generic picture from MP:
Granted, I know I'm walking into uncharted territories here (not to mention that there isn't any record online of anyone actually trying to use this bracket on their Magnum conversion). Just the same, I'm not willing to ring Lokar's door just yet. Unlike any home kludge, this bracket has a hole in it which was (supposedly) engineered by Mopar to fit the upper kickdown bellcrank right where it belongs.
Problem #1:
The P4876314 bracket has provisions for a bellcrank pivot stud, but the original stud is swedged to the throttle bracket. It's not a serrated press-fit stud - trust me, it's impossible to push the stud out and reinstall it with a hydraulic press (ask me, I tried). Not unless the round end on the stud side is aluminum, and it's been heated and cooled to seat permanently around the steel stud.
Either way, the new bracket is obviously designed for a press-in or bolt-in piece. The stock image doesn't show one, I don't know of any part number to find it (MP's catalog doesn't list the bracket either - surprise), and Googling has been of no luck (nobody else references this part other than a few retailers). That includes searches for "serrated pins," "serrated threadless bolts," and "serrated studs."
Which brings me to my first question: Were any factory Mopar SB brackets made with a serrated stud unlike my '68 bracket? Or were they just too damn lazy to make the stud?
And then, question #2 (best asked in a Foghorn Leghorn voice): Did MP ever issue a manual for this stinkin' little part?
Now if the stud doesn't show up, I can always cut the swedged end off the stud and weld it into the MP bracket - which is probably the only option, but I'm not going to take guessing as an answer until I've exhausted all possibilities (yes, even sending an email to MP - bet that'll help! :banghead:).
Which brings me to problem #2, which is the reason I suspect a manual might actually exist for this thing:
There is no indication which factory donor kickdown linkage (at the carb-to-bellcrank location) is supposed to be used with this piece. And, of course, this has been a black art mystery ever since Mopar ever invented the concept of designing a kickdown linkage that has a drawn reciprocation dingle arm built into it (I wonder if I got the optional turbo encabulation?). In short, I'm left wondering whether I need a 340 kickdown arm at the carb, or whether I can stick with the 318 unit.
My guess is the 340, just by virtue of the MP conversion bracket's design vs. the stock 318 bracket vs. the stock 340. Almost certain the 318 arm would interfere with the throttle cable if mounted to the conversion bracket:
318 2-barrel Carter:
340 4-barrel Edelbrock/Carter:
-Kurt
I'm splitting this off from my Maglam (Lagnum?) conversion thread, as it is about time the Mopar P4876850 conversion bracket gets some attention (seeing as there isn't a single discussion that I can find about its use on Google) to see whether it is actually possible to get kickdown working on this thing without welding - or whether it's another dead-end Mopar Performance part.
Until I received mine in the mail yesterday, all I knew of this bracket was this generic picture from MP:
Granted, I know I'm walking into uncharted territories here (not to mention that there isn't any record online of anyone actually trying to use this bracket on their Magnum conversion). Just the same, I'm not willing to ring Lokar's door just yet. Unlike any home kludge, this bracket has a hole in it which was (supposedly) engineered by Mopar to fit the upper kickdown bellcrank right where it belongs.
Problem #1:
The P4876314 bracket has provisions for a bellcrank pivot stud, but the original stud is swedged to the throttle bracket. It's not a serrated press-fit stud - trust me, it's impossible to push the stud out and reinstall it with a hydraulic press (ask me, I tried). Not unless the round end on the stud side is aluminum, and it's been heated and cooled to seat permanently around the steel stud.
Either way, the new bracket is obviously designed for a press-in or bolt-in piece. The stock image doesn't show one, I don't know of any part number to find it (MP's catalog doesn't list the bracket either - surprise), and Googling has been of no luck (nobody else references this part other than a few retailers). That includes searches for "serrated pins," "serrated threadless bolts," and "serrated studs."
Which brings me to my first question: Were any factory Mopar SB brackets made with a serrated stud unlike my '68 bracket? Or were they just too damn lazy to make the stud?
And then, question #2 (best asked in a Foghorn Leghorn voice): Did MP ever issue a manual for this stinkin' little part?
Now if the stud doesn't show up, I can always cut the swedged end off the stud and weld it into the MP bracket - which is probably the only option, but I'm not going to take guessing as an answer until I've exhausted all possibilities (yes, even sending an email to MP - bet that'll help! :banghead:).
Which brings me to problem #2, which is the reason I suspect a manual might actually exist for this thing:
There is no indication which factory donor kickdown linkage (at the carb-to-bellcrank location) is supposed to be used with this piece. And, of course, this has been a black art mystery ever since Mopar ever invented the concept of designing a kickdown linkage that has a drawn reciprocation dingle arm built into it (I wonder if I got the optional turbo encabulation?). In short, I'm left wondering whether I need a 340 kickdown arm at the carb, or whether I can stick with the 318 unit.
My guess is the 340, just by virtue of the MP conversion bracket's design vs. the stock 318 bracket vs. the stock 340. Almost certain the 318 arm would interfere with the throttle cable if mounted to the conversion bracket:
318 2-barrel Carter:
340 4-barrel Edelbrock/Carter:
-Kurt
