[Gopher711]

Took the old hag out last weekend for a thrashing and she has a slight miss , found #1 plug oil fouled and header tube dripping oil out water weep hole. Not bad for 10 + years on GM crank , 3/8" rods and TRW pistons I guess ? Looking at a Howard's 4340 Crank or Callie's Compstar with Oliver Billet Rods 6.538 " and Ross custom pistons Old compression was at 8:75/1. Looking to stay blown gas or possibly Inj alky in future. What would be a good compromise on compression ratio to have that option ? And how stout are GM cranks and 4 bolt block. I have ARP studs throughout already. Upgrade to billet caps ?? What would you guys do ?.. Might just be valve seal , maybe cracked ring , but whatever it is I think I've pushed my luck long enough LOL. Bottom end and rotating assy will be upgraded to best available parts I can afford hopefully soon ! What you guys think on cranks ? Upgrade to Callie's Magnum or Howard's Pro Max over the Compstar ?. It only a few hundred more for the Howard's and about $500 more for the Magnum ?

 

[sammyc57]

You can forget that wishful thinking valve seal shit, as far as anything else I don't think your gonna find a "good" c/r to go from blown gas to inj. alc., I would think yould be better off going in the other dierection from blown alky to n/a gas. But im sure somebody with more expertise will come in on this.

 

[Gopher711]

Nobody ???? 6:shock: Pulled heads , cylinders don't have a ridge at top but some holes have some vertical scarring I guess from side loads on pistons as they are at the bottom sides of cylinders

 

[sammyc57]

I told you that valve seal idea was just wishful thinking. Enough oil coming through a valve seal to foul the plug would pretty much have to be plugged oil drain back holes plugged with sludge in the heads. Maybe someone will give some advice as far as comp. ratios on the alky-gas,gas-alky deal. Hope the new build goes well.

 

[jimclauss]

I told you that valve seal idea was just wishful thinking. Enough oil coming through a valve seal to foul the plug would pretty much have to be plugged oil drain back holes plugged with sludge in the heads. Maybe someone will give some advice as far as comp. ratios on the alky-gas,gas-alky deal. Hope the new build goes well.

Blown Alky likes 11 to 1 and up,NA alky 13 to one, Blown Gas 8.5 to one or more, ( depends on
octane ) put it on a dyno

 

[Gopher711]

Gonna try and shoot for 9:1 static comp and run gas for now , got a good friend running in PE class ( Jaw Droppin Express ) on Blown alky on a similar small cubic inch BBC ( 427 stroked ) running just 9:1 and he's won the PE Class a few times so evidently it works , maybe not the ideal ratio but workable So I'm basically going to be copying his build