mike tkach

iTrader: (3)

my point is simple,as i said i have never had a problem with a pro 1 head.i dont walk on water or have a magic wand,but i do pay attention to detail,maybe that,s why i don,t have the problems you have.no need for you to be a smart azz.for you to make a statement that the pro1 head has issues is completly false.maybe you have issues,just sayin.you are famous for posting up incorrect information,but carry on,it is the internet!

mike tkach

iTrader: (3)

and just fyi,the op probibally does not need you to tell him his,and all pro1 heads have issues!

Rookie

iTrader: (4)

I have seen a broken boss as stated by Black Baja on a Pro1 head. This head had the wrong rocker studs in the head. The PRO1's need the longer stud that protrudes past the boss and into the head. ARP has a special part# for Pro1 heads.

Dart:
"ROCKER ARM STUDS
All Dart big block heads use an exhaust rocker arm stud with an increased thread length where it is installed in the cylinder head. It has a 1.300” thread length for the raised rocker arm boss. Do Not Use a Shorter Length. Part# Dart 27002204 exhaust stud Dart 27002223 intake stud ARP 235-7202 Kit"

https://www.google.com/url?sa=t&sour...iBCVp6GJwPbuHg

mike tkach

iTrader: (3)

100% correct,the afr head also uses that stud.hardly a geomitry problem but a builder error.

14 apache

iTrader: (1)

that don't look like the rocker stud looks more like the cup side of the rocker hitting.

Tinkerer

The mark IS from the lock nut. I will be going out in the garage soon to finish tearing apart the Daytona. I will check out the valve train.

MILD THUNDER

iTrader: (3)

I've seen several used dart heads, that have had incorrect rocker studs installed in them. Guys slap in a "general" set of 7/16 rocker studs, that typically have a threaded portion of .700, when they should have used the proper stud, that calls for 1.300 on the exhaust. I've seen that setup hold up ok in a low rpm, low spring pressure basic marine engine, but certainly doesnt hold up with higher spring pressure setups, esp with the amount of force needed to open the exhaust valve when its opening against cylinder pressure. Yes, the bosses can break when that happens.

I have many many friends running Dart Pro 1's, or race series heads. From mild 600hp marine engines, to 1000+hp blown marine engines, for years, that have not had any issues.

dereknkathy

stud girdles anyone?

mike tkach

iTrader: (3)

a stud girdle helps keep everything in place but it won,t fit under the stock merc 500 style valve cover.

Rookie

iTrader: (4)

If I was buying all new again I would just go with T&D or Jesel shaft system. After adding up new studs, new rockers, adjustable guide plates and girdles it's just a few $$ more. Granted, i'm not using girdles so that is a $315 savings.