I have been working on my 081 casting 305 heads (for my boat). Machined down stud bosses and tapped for screw in studs, cut down the top of the valve guides for more lift, gasket matched, and, ported the S**T out them. Also did a 5 angle valve job and unshrouded the valves.

Does anyone know if you need to mod the pushrod holes in the heads or not? I am waiting on a set of 1.6 roller rockers, so I havent been able to check. If I do then I might just drill them all the way out and run guide plates.

 

i dont think i've heard of anyone haveing pushrod hole problems. guideplates tho are fairly cheap and work ok, so its a safe bet.

i've seen many hotcams and other cams with 1.6 rockers and not seen a problem with pushrod holes/clearances

 

Mine fit fine. I have heard of others having to drill though. Date code on my heads indicated december 1989. LT4 cam and 1.6:1 roller rockers

 

What did you do to get your factory steel valve covers to go on? The rockers I bought have really wide bodys and are hitting the steel braces inside the covers. Did you have to trim those out?

 

yah u need eier narrow bodied rockers, or some cutting and grinding, most are against cutting them up but, idone it with no problems.

 

What do you think of a ramjet 305 with an lt4 cam, 059 or 520 casting heads? 1.5 or 1.6 rockers?