Valve cupping? why? Anyone?

[Mkos1980]

Re: Valve cupping? why? Anyone?

Well, from reading a few posts from the front he mentions his casting numbers on the heads and those are the older type heads. 8 posts ago there is mention of a differant long block installed. I can care less the thread is 3 months old. The last post was only a month ago .

 

[Riv]

Re: Valve cupping? why? Anyone?

Jegs sells several Edalbrock manifolds that are made for the cast iron Vortec heads, arround$260.00. They also can get you the marine webber from Edalbrock. I'm using the 1409 Webber (Edalbrock carb) Cost $320.00 at local shop. The manifold I selected is the Edelbrock performer aig gap. They also make it for the cast iron vortec heads p.n 350-2604. At the local shop mine cost $200.00. The vortec type may be a littlt moore. If you want to call them, the # is 815-727-6331, ask for Jim, he knows his stuff.

 

[CharlieB]

Re: Valve cupping? why? Anyone?

I know it's rather late, but it is clear as mud what happened to cause the problem.

The ORIGINAL motor was a 305, the merc dealer/mech (supposedly) granted the customers wish for 'more power' during the initial rebuild and substituted a 350 shortblock in place of the correct 305, BINGO, destined to fail.

The heads were correct, originally, however, when displacement was increased, the heads should have been changed also by ordering the longblock.

Reinforces leasons previously learned, be vary careful in altering original configurations.

 

[mtnrat]

Re: Valve cupping? why? Anyone?

The Qjets work fine. BUT make sure it is a marine carb. If not do not use it.

 

[FreeBeeTony]

Re: Valve cupping? why? Anyone?

Another 350 with 305 heads?????

 

[Bondo]

Re: Valve cupping? why? Anyone?

Another 350 with 305 heads?????

Ayuh,...........

It's Truely Amazing how many people Think that a SBC Head, is a SBC Head........
There have been literally 100s, maybe 1000s of variations from Chevy over the last 50 years.........
Obviously,.... Some are Better than others,........ That's Why Chevy has always used Casting #s........

As long as you can do the Research,+ Understand which parts would be the Best Choice,....
For Your Application.........

There's Nothing Wrong with having the Best Parts available,...... As Cheaply as possible.......

 

[TilliamWe]

Re: Valve cupping? why? Anyone?

the other reason I see quite often for swallowing an intake valve on a 5.7 is engine lugging due to over propping for the current hull loading.
I usually try to prop most 5.7 motors to turn 4800 or so when empty.
but a swallowed valve is a symtom not the problem.

Or a dirty bottom. Right on the money rodbolt.