I am going to pull my stock 290 heads off this winter to check valve guides for oil consumption.I'm wondering what else I should have done to them while I have them at the the machine shop.I've heard have bigger valves put in,pocket porting,deshrouding,and other terms ,not sure what all that means.Im just looking to gain a little performance while I have them off ,but I dont want to effect reliability.With the pistons I'm running I'm up around 11 to 1 CR and would also like to lower that a little if possible(thicker head gaskets?) so I could run 93 gas.My engine is a stock bore 70 LS-5,TRW forged L2465 pistons(195 cranking psi all 8 cyls),Power Plus cam .544,.544 lift,230-230 dur.,Edelbrock C-396,Holley 770 Avenger,complete MSD setup 4 spd,3:73 rr.Mostly cruising,about 3,000 miles a year.Thanks all.

Yah put the larger valves 2.19 - 1.88 , you could have the chambers ground for deshrouding (open the chambers up for better air flow) ,and this will lower your compression also , not much but with a thick 60 thousands gasket (cometic ,mls ,etc).you should get down to 10.1

Careful with thicker head gaskets - widening your quench out may make it more prone to detonation with lower compression. Has the block been decked, etc.?

No, the block has never been decked.

Your combo aint all that rad. Id bet more than anything, the biggest gians would be found with opening up the valve throat a bit and working in the bowls some. Smooth off the short side radius a bit too. If you take it to a descent head porter....they will know exactly what your talkin bout if you mention this stuff.

Larger valves wont hurt.....I just cant say how much they would help on a mildish combo. But if it came down to doing on or the other based on money you can spend......Id suspect stock valve sizes with descent valves and mild port work(the stuff I was speaking of before) would provide a greater gain than leaving the ports as cast but just putting in larger valves.

Next in line....I wouldnt go with the larger gasket. It can hurt more than it helps sometimes. This effects quench(as mentioned earlier)....and it effects it in a negative way. One of the side effects of poor quench can potentially be increased detonation even with the decreased compression. Open up and unshroud them chambers a bit as is. Give em a polish job while your at it. It doesnt sound like your beyond the limitations of pump gas with a lil work and a good tuneup.

Thanks for the replies ,thats what I'm looking for.What would I expect to pay for this kind of head work,ballpark.

Doug, You may already be aware of Ladds Porting Service. I spoke with them about prices and they did not seem out of line to me. I know they do great work and have all of the best equipment. They will be doing a set of heads for me this winter.

http://www.laddporting.com/

Dave

Hi Dave,yes Ladds has been around forever,I was going to wait till I got my heads off and checked my guides before I called around for pricing.There is another outfit up in Lancaster called Racekrafters,dont know anything about them but I read and interesting article about them in Hemmings.I'll probably check them out too.I usually have Kunkels or J+B do my machine work but not sure if this is there forte. Thanks ,Doug