Pushrod length

[butch27]

Do Ford 302"s AFTER 1969 use 6.905" pushrods or the stock 6.804" ? Thanks I have a '78 with '72 heads.

[wayne petty]

Melling/Pushrod
For your 1972 Ford 5.0L 2BL OHV 8cyl
Part Number:   MPR-281
Warranty:    1 YR
Notes:    For use with hydraulic lifters.

Melling/Pushrod
For your 1978 Ford  5.0L 2BL OHV 8cyl
Part Number:   MPR-281
Notes:    From change L4.


MPR-281 + 6.876"

here are the 2 pages everybody who works on push rod motors needs to have on the wall...

the melling push rod dimension information..

http://www.mellingengine.com/Portals/5/pdf/pdf_catalog/push-rod-identification-chart.pdf




this is how you verify that you have the correct length push rod..  with collapsed lifters..    new lifters that have not had oil pumped into them..

Repeat this procedure for all of the cylinders, using the firing order sequence as a guide. It takes 1 / 4 turn of the crankshaft to bring the next piston in the firing order sequence up to TDC at the end of its compression stroke. Collapsed Tappet Gap Clearance:



Allowable: 0.071-0.193 inch (1.8-4.9mm)

Desired: 0.096-0.165 inch (2.4-4.2mm)


there are from most manufacturers +.060 and - .060 from standard length push rods ...  

to take up for milled heads and blocks ..
machine the block and heads.. might require shorter push rods


to take up for variations in cam base circle diameter...  
 cam regrinders have to grind off the base circle to give you more lift and duration.. different lobes maybe ground different

to take up for variations in valve stem installed height...
grinding the seats moves the stem height up... grinding the valve faces moves the stem up..    new valves and or new seats might keep it where it was at the factory..


the longer and shorter push rod part numbers are usually found in Elgin engine parts catalogs..


302

1968/69

"Before chg. / L4" C2OZ-6565-B .. Pushrod ~ 6.825"-long hydraulic tappets
------------------------------------------------------------------------

1969/

"after chg. / L4" C9OZ-6565-B .. Pushrod ~ 6.905"-long hydraulic tappets

D0OZ-6565-C .. Pushrod ~ 060" U.S.

D0OZ-6565-D .. Pushrod ~ 060" O.S.
-------------------------------------------------------------------------
68/70 C9OZ-6565-F .. Pushrod ~ mechanical tappets = 6.950" -long hardened steel


more reading

http://www.compcams.com/information/Products/Pushrods/

[chimp koose]

I believe it was after72 that the pushrod length was changed.351W had longer pushrods as I recall.I put a set of 69 351W heads on my 289 and used the early short pushrods because I milled .080 off the heads. ( if jack roush could do it to the 79 indy pace car motor I thought I could too.)There was an article in hot rod in79 describing the roush motor used for the indy pace car mustang that described the pushrod issue quite well. probably the may issue I think.

[wayne petty]

roush....  hmm

http://www.mustang50magazine.com/techarticles/14625_roush_racing_used_parts/index.html


notice the address in michigan...  only 2300 + or - miles ... i wonder if i can talk my wife into a parts trip...

[enjenjo]

roush....  hmm

http://www.mustang50magazine.com/techarticles/14625_roush_racing_used_parts/index.html


notice the address in michigan...  only 2300 + or - miles ... i wonder if i can talk my wife into a parts trip...

Less than an hour from me.

[butch27]

Thanks:  Had one short one-(6.801) from a new set I bought.