817 heads

6

60biscayne

Active Member
Supporting Member 1
I have a set of 817 heads that look fairly fresh, but I think I'm going to have them gone through again anyway. The exhaust valves in it are already stainless. My 1st question is: should I purchase stainless intakes?? We are looking to put out about 380-400 HP., for mostly street driving. We will be using 11-1's in a truck block, (409), somewhat large Hyd. cam, headers, 750 CFM AFB, etc. My 2nd question is, would it be worth the expense to have the heads machined up to accept the larger 2.19 Intakes? About how much HP. increase would I see with the larger intakes? Ballpark?? If I did have the machine work done, I might as well buy the SS intakes. I've got a whole new set of springs. Thanks! 60biscayne! :p
 
Fathead Racing

Fathead Racing

Well Known Member
Supporting Member 7
You will be very happy with the 817 heads just the way they are with the 2.06"/1.72" valves for street driving and an occasional blast down the strip. As a matter of fact the smaller ports and valves of the 817s are better suited for a street car and will give you more low end torque and better throttle response. I would replace the intakes with stainless valves. To trick your LoPo heads I suggest you do a mild port job. You can gasket match the intake ports and blend them into the runners about an inch or so, narrow the valve guides in the bowl and cut the ridge just below the valve seat. Do an overall cleanup with a die grinder and some carbide cutters leaving a pepple finish not polished, port mach your intake also. I just had a set of 690s tricked out at the machine shop an dropped 1470.00. Not cheap! And I did my own porting. The lions share of the cost is in the machine work with parts accounting for about a third of the total. :eek:


PS, easy on the cam selection, those same heads need a cam that is matched to your port flow. A somewhat large cam will kill your bottom end and the heads will not flow enough air to take advantage of the big profile cam.
 
LongIsland63SS409

LongIsland63SS409

Well Known Member
Supporting Member 3
Fatride:

If you were to pick a cam to match the mild porting what would you select?

Lots of computer time today with 9" of snow on the ground with more coming down:grumble:

Thanks,
Mike
 
models916

models916

Well Known Member
Supporting Member 7
change the stock valves

Screw in studs and SS one piece valves on todays cams, springs, no lead gas. Fast setting ramps and high spring pressures wil pull the heads off the old valves. 817 heads are the best STREET head.
 
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