Longer pushrod question?

ike34

Member
Jan 16, 2004
156
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19
Waterloo, IA
My friend has a 94 v6 mustang and he says he is going to put 10 thousandths of an inch longer pushrods on his intake valves and 5 thousandths of an inch longer on his exhaust valves. He says he is doing this to get a lopey sound and some power. He also said he is going to use pushrods from a 302. Is this worth it, is it going to give him any noticable lope or power. I was just wondering because it dosent sound like it will work or be worth it? Will it?
 
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Ok well, i got to thinking about it, and i dont really think this will work, making them longer i believe will cause a problem because

1. If the rod goes to open the valve, and it pushes the rocker past its stoping point, it just might bend the rod.
2. Lets say that does not happen, when the cam goes back down and the spring pulls the valve closed again, due to the rod not being of the proper size for the cam, the valves would stay open just a bit then, you would have a nasty little problem, the engine would go to compress the air/fuel mixture and it would escape from the intake and exhaust valve, and whats left there would be ignited by the spark plug and KABOOM! the fire would spread through the intake manifold and through the exhaust and i dont think it would end very well at all.

But thats just my 2 cents.
 
OK, best case scenario is that he gains a little more valve preload and maybe gains a hp or 2 from that, being that the valves would open quicker than they would with slightly less valve preload. The car will not LOPE noticeably more, if at all, because you are not going to get significantly more valve overlap or duration.

Worst case scenario is suggested above. With TOO much valve preload you have valves that don't even close. Basically, his engine will either no longer run, or run so crappy it's not even funny.


Finally, IIRC, 5.0 pushrods are .5"+ SHORTER than 3.8 pushrods. I could be wrong, but either way, the whole thing seems like a dumb idea. If you're going to that much trouble, you might as well put in at least RR's if not a cam or ported manifolds. It certainly isn't worth while even if it doesn't screw up his car.