Rebuilding heads need serious help

[Bad Snake II]

Hi,
I have been wanting to rebuild my origional heads for performance and to keep the same parts on the engine it came with. one problem, the only valves i can find i am interested in are made ither for 351w or are for 289-302 but have been lengthened .050 in. Are the 351w the same thing or not. and as for pushrod guide plates i can only find them for 351w and they have to have special fitting to each pushrod and have to have special studs (i am going to screw in studs ither way). I also want to get them ported and polished, and decked a bit maybe .010 or so. they are the 68 302 non cast in pushrod guide and have 52 or 54cc chambers heart shaped. on speed pro flat top hiperutectic pistions will that .010 deck raise my compression to 11.1 or more.
Or i got a set of 66 289 hipo heads with cast in pushrod guides and 52-54cc chambers heart shaped. I want to put screw in studs in so will it be better to stick with the origional 302's or go with the 289 hipo's. with the hipo's will i still have to get a set of guide plates.
This is a link to the valves i want but they are .050 longer than stock.

http://store.summitracing.com/default.asp?Ref=MFG&N=120+400380
go to the engines and components then to cams and valve train then the mega flow valves. bottom of page one. both intake and exhaust.

with a radical cam that .050 could put the valves through the pistons right or am i beeing to critical. the only other way i think i can solve this problem is have my machine shop take the .050 off the top of each one, if the keeper slot hasent been moved up .050 also.
Feed back please.

 

[Ronstang]

When done you are going to have a set of heads that cost almost as much as an aftrmarket set of heads would and they won't perform nearly as well. There are lots of used aftermarket heads on the market these days that are great deals....just paint them blue and go.

 

[Bad Snake II]

do you mean alluminum heads. I had a friend that put $1,800 in a set of aftermarket aluminum heads and he ran them a week and they were warped so bad the valves would hardly open. do people make a good sat of cast iron ones or will you recomend a set of alluminum ones.
thanks

 

[Ronstang]

I have never had problems with any aluminum heads, even the older ones that people claimed had warping issues. Your friend either extremely overheated the engine or installed the heads improperly or both.

Look for used heads. They are everywhere these days. There are always those speedfreaks that chase every last HP and have to have the latest and greatest so the used market has lots of good deals on heads. You can look for some used cast iron units also like the ones from Ford (GT-40), Dart, and World Products but I would go with aluminum. Keep an eye open and you could find a good set of aluminum ones on the cheap.

I'm not going to recomend any specific head since all are leaps and bounds above stock units. If you could find a set of Ford GT-40X heads used for a good price then you would be in pretty good shape if you want pedestal mount rockers. All the other brands have both pedestal and stud mounted rockers so decide what you want and start shopping.

 

[retro50]

Usually when I do these heads, I'll go with the 69-70 351-w valves. Or aftermarket Manley performance valves. The factory replacement valves for the 351-w measure 1.840" for the intake and 1.540" for the exhaust. The overall length is 5.070" The Manley performance valves also are offered in the 5.075"length and valve sizes of 1.850",1.940"for intake an 1.550",1.600" for the exhaust. They offer 4 different valves all with the same length.They are also offered in stainless steel with undercut stems. If you go for any of these valves,Have your machinist cut in the valve seats to fit the valves and to shoot for a Valve stem height dimension of 2.157"-2.187" This is the spec from Ford. This dimension is measured from the tip of the valve to the valve spring seat.If you go this route you can use the Comp Cams 972 springs and matching retainers and keys,to achieve a spring installed height of 1.800". These springs are a single spring with a dampner and I believe there good for .550 lift. There will be minimal shimming needed. Doing it this way you should be abe to run the stock length Mid to late 70's pushrods Hardened if you use guideplates. but you will have to check the valvetrain geometry anyways. As far as the screw-in studs and guide plates,Manley or comp and most cam companies offer them for the small block Ford motors. This is a easy conversion and any machine shop should be able to acomplish this. As far as your compression goes have the heads c.c.ed to find out your true compression ratio.Without c.c.ing your only guessing in the dark. If you keep the valve lift to around the .500 lift figure You probably won't have any problems with the piston to valve clearance. But you should always check it anyways.

 

[cobra1]

get some afr's and "fuggetuhboutit"

 

[D.Hearne]

Hi,
I have been wanting to rebuild my origional heads for performance and to keep the same parts on the engine it came with. one problem, the only valves i can find i am interested in are made ither for 351w or are for 289-302 but have been lengthened .050 in. Are the 351w the same thing or not. and as for pushrod guide plates i can only find them for 351w and they have to have special fitting to each pushrod and have to have special studs (i am going to screw in studs ither way). I also want to get them ported and polished, and decked a bit maybe .010 or so. they are the 68 302 non cast in pushrod guide and have 52 or 54cc chambers heart shaped. on speed pro flat top hiperutectic pistions will that .010 deck raise my compression to 11.1 or more.
Or i got a set of 66 289 hipo heads with cast in pushrod guides and 52-54cc chambers heart shaped. I want to put screw in studs in so will it be better to stick with the origional 302's or go with the 289 hipo's. with the hipo's will i still have to get a set of guide plates.
This is a link to the valves i want but they are .050 longer than stock.

http://store.summitracing.com/default.asp?Ref=MFG&N=120+400380
go to the engines and components then to cams and valve train then the mega flow valves. bottom of page one. both intake and exhaust.

with a radical cam that .050 could put the valves through the pistons right or am i beeing to critical. the only other way i think i can solve this problem is have my machine shop take the .050 off the top of each one, if the keeper slot hasent been moved up .050 also.
Feed back please.

First of all, 351W guide plates are the same as ones for a 289-302. Second of all, if your heads are 68 302 heads, then they already have the longer valve stems ( for rail rockers) so that's not an issue. All screw in studs for 289/302/351W should be interchangeable, after all the head's dimensions are all the same as far as the stud/valve layout. You say you have a set of 289 Hi-po heads, what makes you think they're GENUINE Hi-po heads? If they are genuine, then sell them to someone who needs them for a restoration and use that money towards a set of good aftermarket iron heads ( if you still don't trust aluminum ones) Valve stem length has nothing to do with the gross valve lift. It does require checking the geometry and adjusting it accordingly.