looking for best heads for stock replacement

ashford

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Dec 19, 2003
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i have a rebuild explorer motor in my old falcon and the heads are giving me fits. i have rebuilt them twice and for some stupid reason the exhaust seats keep warping and not sealing after about 300 miles and give off the sewing machine noise about the same time. they WILL be going into the scrap iron. i have been looking for economical replacement heads that will yield longevity and similar power.

i am stuck between edelbrock e- tec, iron rhs and for for x306. so far im leaning toward the fords due to i can reuse my rockers(scorpion) and the valve covers should fit.

the engine is basically stock with an ho cam and 70mm tb. i tried a trickflow stage 1 and it was a little too temperamental for me. 250hp that runs stock like and quiet is my goal.

which heads are normally the least problematic for the long haul?
 
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ashford

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Sure it's not your rockers making the sewing machine noise?
absolutly, there was no difference from stock to roller rockers, 3 set of pushrods. 2 sets of lifters, 2 sets of springs. the only time it quieted down was when i had the heads rebuilt for the 2nd time then slowly came back in about 300 miles
 

2000xp8

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You doing this head work or a machine shop?
If it's you, just take them into a machine shop for a valve job.
 

ashford

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with the stock exploder cam i had 1 1/4 turns on the rocker from no load to seated, ran it for awhile till shorter ones came in. i got them and installed em. it was at half turn give or take a little. no change. at this point i figured the freshened up 200k motor had bad pistons(piston slap when cold) so i rebuild the short block it replaced, threw in a tfs stage 1 cam and had the same problem(btw the tfs cam has a smaller base circle than the oe cams) tried new lifters, then different springs.

at this point i figure something is wrong and pull the engine out for a complete tear down. the shortblock looks really good. i pull apart the heads and when i push the valves in the heads with hand pressure i can see light about a 1/3 the way around the valves. i had the heads rebuilt again( the first time was when i freshened up the exploder motor) put it all together and it ran quiet for about 50 miles and then slowly began ticking away till it was where it was before after about 300 miles.

if i pull the head apart again im willing to bet the valves aren't seating right.
 

ashford

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You doing this head work or a machine shop?
If it's you, just take them into a machine shop for a valve job.
i brought them in for a valve job, they replaced the exhaust guides and knurled the intake and a simple 3angle valve job with new springs.

i used to have the equipment to grind valves and seats. but it was ancient stuff and worn out. the gibs were loose and the table wasn't quite true to the motor axis. a good learning experice but nothing i would use on anything worth a damn.