heads big heads witha lot of flow are great but u betta have the cubes to pull it stick with the small suff and ya can't go wrong good flow/velocity
well... i bought heads bare and had them fullyported and machined for a.739 roller. here's where the problems started... heads will accept lifts to .750 ,now to control that kind of spring pressure we went with comp's best spring(nascar spring)the spring that is supplied with head would not lastwe also had to go with longer valves. whatever valve supplied with heads are cheapos(we used ferrea's) when we started chking angles and valve train geometry we found out lot of problems. intake pushrod (3/8 pushrod) hitting edge of head to eliminate this and to get a good lineup we had to go with a offset lifter on intake side. exhaust side fine we called kaase/jegs and explained our clearance problem. their answer mill head to make pushrod fit!!! this cannot be done due to possibly milling right into head . the pushrod was right against head!!!! so we got figured out and went to put out pro-mags rockers on.they wouldn't fit!!! remember,these valves are canted toward each other so the trunions on the rockers will touch!!!again i was on the horn to jegs. i claimed they said everything was bolt on but this was not happening in out case. we miked the narrow trunion distance and started to search the world for a narrow rocker to fit. low and behold jegs rockers is the only that will work. and it has a big relief on the underneath side for the monster spring we had(anything stock will bolt on ,ya right)jegs kaase did not do their homework when somebody was installing a high lift cam. a smaller cam might work but risky. i blew 6k trying to get this set up to work. they did make a stud girdle for it though. the rockers showed evidence of massive side loading too. i did bolt the heads on my 347 and ran them a half season. the combo was way mismatched those heads flow like a banshee but require lots of cubes. to put it in a nutshell. don't try it until everybody is using it. afr/edlebrock/trick flow/canfield/ to name a few are good bolt on heads that don't require alot of wallet to get em to run well to this day jegs still runs that add about those heads!!!! ps i sold em to a dude in hawaii that is doing a large cube stroker small blk mike
