I just joined the forum a week or so ago and already have a problem to throw at you.
My step-son has a 72 Bronco that we are putting a 5.0 with 351W heads in.
The short block is from Summit with roller cam, and he got new roller lifters, needle bearing roller rockers and new push rods and guide plates.
He got an ARP bolt kit so we have the correct head bolts with the the sleeves etc. He had the heads redone with new valves and screw in studs they had already been clipped for a small block.
When I assembled the valve train I noticed some of the rockers were very crooked, in fact on about 6 of them the roller on the rocker only covered about 1/3 of the valve stem.
What do you guys think might be the problem?
Any help greatly appreciated.
Sorry for the long post, wanted to get as much info as possible out there.
Change the pushrod length..
Yes mark valve stem with marker, turn engine over and contact area should be nr the middle..Sounds like geometry is slightly wrong..With guide plates you need hardened pushrods...What heads are they ?
Talk to the tech guys at summit...
Don't be afraid to try something new. Remember, amateurs built the Ark...Professionals built the Titanic!
Tuned & maintained by "Peppertree Perfmormance". Dart block, Scat 4340 steel crank, Custom C.P pistons.Oliver rods.. Mal Wood twin plate clutch.. Twin SC61/2's,482 rwkw/ 645 rwhp..
Passengers, myocardial infarction material..
The heads are just stock cast iron 351 heads. Yep, the geometry is definately wrong, just wondering why.
You think shorter pushrods would do the trick? I think I have an adjustable pushrod in my garage somewhere, I'll hunt it up and do some experimenting.
The 351 must have more meat/ bigger combustion chambers...Heads sit higher...??? Or different ??
Yeah, all those things. I've tried different length pushrods and nothing. I'm going to have to go to stock rocker arms and lose the guide plates to get thing to line up, unless someone can come up with a way to move the studs or the valve spring pockets.
The rockers are FMS. I'm going to buy them and the guide plates from my step-son and have him get some self aligning rockers. I have a set of Cobra heads that will eventually see duty on a Factory Five Cobra that is my next project, so I can use the stuff on them.
Thanks for the help, I'll let you know how things turn out.
351W heads are taller than 302W heads and need longer push rods and the bolts are bigger diameter (I think 1/2" thread instead of 7/16"). FMS SVO catalog has the part no or use ARP head studs (easier).
With the rockers they maybe for a Clevo setup (ie 1.70:1 or 1.73:1 ratio).
Good Luck !!!
The AutoGuide.com network consists of the largest network of enthusiast-owned enthusiast-operated automotive communities.
AutoGuide.com provides the latest car reviews, auto show coverage, new car prices, and automotive news. The AutoGuide network operates more than 100 automotive forums where our users consult peers for shopping information and advice, and share opinions as a community.