decking the head?
#1
decking the head?
I just picked up some spare 289 heads to do some serious work to. One of the things I'd like to do is deck the head to pick up some extra compression. Any builders here have an idea on how far I can go?
Using standard flat-top pistons, planning on oversizing the valves though.
Full plans on the heads include a race port on both the intake and exhaus ports with a polish. Oversized valves and stronger valve springs. Still deciding what I'm going to do with the lifters and such once I get my cam in order. Going hydraulic roller though if it makes a difference.
Using standard flat-top pistons, planning on oversizing the valves though.
Full plans on the heads include a race port on both the intake and exhaus ports with a polish. Oversized valves and stronger valve springs. Still deciding what I'm going to do with the lifters and such once I get my cam in order. Going hydraulic roller though if it makes a difference.
#3
As far as materials I'm looking at having to buy new pushrods, valve springs/retainers, valves, and rocker arms/studs. Also gonna put new plugs in the water holes and replace all the gaskets.
Bringing the camshaft into it I'll have to buy hydraulic lifters as well as the camshaft.
I don't have a good cost yet because I don't know exactly what I need to get. I'd like to get the porting/decking done before I spend any money in the machine shop in case I mess it up, but at the same time part of me thinks it would be good to do the valves first so I don't take too much material off, though I could probably get away with simply marking off the valve holes.
The fact is the most I've ever done is port-matching on my hi-po heads. it came out pretty good so I figure I'll try my luck with an extreme port-polish.
Last edited by jojobanks; 01-02-2012 at 02:41 AM.
#6
Basically I'm going to wait on everything else until I can see what kind of porting job I can get done on the head. I'd hate to spend all kinds of money just to mess up the heads, say screw it and buy a set of aluminum heads, and end up trying to get my money back for a whole bunch of useless stuff.
Once I get the heads ported, decked, and flow-tested then I will start ordering stuff to build them.
all that said, how far can I deck the head? I'd love it if someone knowledgable could help me out, otherwise I'll have to wait until the valves are in to be able to keep track of valve/piston clearance while decking.
I'm going to be going with intake-2.020/exhaust-1.6 valves. probably $200
I want to use all hydraulic roller cam/valvetrain, but I dunno if I can keep to $500 if I do that. I may simply try to increase my budget for this if I can come up with the extra dough. This would cost me around $500 in and of itself.
Last edited by jojobanks; 01-02-2012 at 07:10 PM.
#7
I am not sure on the exact amount but after about .020 or so is shaved off of the heads you start to have alignment problems with the intake and it will need to be machined as well...The 289 heads already have pretty small chambers(unless they are 68s) so there may not be alot to be gained here...Also be careful when doing your porting not to enlarge your port openings in the heads bigger than whatever gaskets you are using..It's easy to get carried away with the grinder..
#8
That's the risk. A good machine shop that favors Ford should be able to help answer all your questions based on their previous work preformed and suggest the right cam as well as what rocker ratio that will work together. Nothing will beat a well conceived plan, this will save you money, time, replacment parts and the biggie, aggravation.
#9
2.02 intakes on a flat top piston is already close if not touchng already depending on the valve lift,decking the heads will probably ended up with PTV contact.On my last engine I had to cut the pistons for valve reliefs with 2.02's and that was without decking the heads.
#10
I am not sure on the exact amount but after about .020 or so is shaved off of the heads you start to have alignment problems with the intake and it will need to be machined as well...The 289 heads already have pretty small chambers(unless they are 68s) so there may not be alot to be gained here...Also be careful when doing your porting not to enlarge your port openings in the heads bigger than whatever gaskets you are using..It's easy to get carried away with the grinder..
I'll be opening the intake up slightly as well but everything will be matched. If I have to trim the gasket back slightly then I don't have a problem with it. My main goal is to stretch these heads as far as they'll go performance-wise. I just worry about possibly going too big and ruining the flow characteristics.