Hey guys. Rebuilding 350TBI motor now. Measured valve guides and they have some unequal wear (on the top and on the bottom difference is more than 0.004").
Heads are iron.
What would you suggest: to cut and install new valve guides, or to get owersized stem valves and to cut guides to proper size?
Thanks.

 

it is sometimes better to bore the guides and get oversized stem valves.

 

rusty vango
Thanks, was actually thinking to do so.

 

obviously, there are only so many oversize valve stems available. if guide wear is too much, you have to go with bronze inserts.

 

If they're "swirlies", throw em in the trash and get better heads.

Wrong core to be sinking money into.

That said, the best repair method for heads that are worth repairing, is bronze sleeve liners.

 

Absolutely...cost to ream a guide to fit an over sized stem, is the same as to ream to fit the liner, sure the liner plus the fit is a few more bucks, but will last 3 times longer than a stock guide would.

 

Cost to buy better heads (e.g. Vortecs) is less than repairing that garbage you got now.

 

Definitely.

 

Yes, these are swirl port heads.
I do not like the idea to change heads as will have to look for other chip in ecm, and I'm trying to stay stock.
Already started to work on a swirl port to "uscrew"it a little.
I'm from Ukraine and shipping of heavy heads will cost a lot. As well machine shop's do not take much to ream the quides (valve seat 3angle work, reaming the guides and decking the heads will cost totally 150-170usd).
Other question, if I will go with oversized valves I should get oversized valve stem seals, correct? Should seals be same diameter as valve stems, or seals should be little less diameter than valves?
Many thanks for adices.

 

I wouldn't spend much time massaging the heads, years back a member actually took the "vane" out, the before and after flow data was pretty much the same.

IIRC, he did pick up most gains with standard blending and working on the valve guide bosses (was done prior to removing the vanes).

But, if you come across a better set of heads, no chip tuning should be required.

By larger valves do you mean diameter, or stem diameter?

Either way, I don't think there are larger seals for just a few thousandths stem diameter, well at least I never noticed them when looking for seals.

 

8Mike9
What I know, even vortec heads do not really work good w/o chip cange.

Summit gives several seals diameter starting from 0.313 up to 0.375" http://www.summitracing.com/int/sear...rder=Ascending
So if i will take oversized stem valves 0.356" what seals to take? 0.344"?

 

Oversized valves is not the customary way of repairing worn-out American heads.

Might be typical in some situations, maybe Lada or Trabant or something, but not this.

Here, we throw crap heads in the trash, and put on the best we can afford or find.

When we already have good heads and they have that type of problem, we use the sleeve type liners.

I have built ALOT of motors over the last 4 decades or thereabouts. I have not used oversized valves EVER, not even ONCE. I have not the vaguest clue whether any such thing is even available or not. We simply don't do it that way on this kind of motor.

The right thing to do is to throw the crap heads in the trash, quit making excuses about "it's hard", and get better heads.

 

sofa - cut this guy some slack, freight cost to the Ukraine will be hard. Heads are heavy and relatively delicate to travel that distance and be re-handled who knows how many times before they get there. That's even before considering that there's always a risk in buying something used.

This is a case where fixing what he has is the most practical option.

 

There's bound to be other junk vehicles; 96-2000 trucks for example. Those things are all over the world.

Regardless, oversized valves are not the way it is done.

 

Sofa.
Lets forget about other heads, I'm fully satisfied with stock heads, and do not need anything more. It's not even about the price, I'm spending big amount for whole car rebuild (my rebuild http://www.impalassforum.com/vBullet...d.php?t=348362). I just need my motor to run and to do not play with chip tuning, etc once rebuild will be finished.
The question is if to go with oversized valves, or to go with inserts.

P.S. This is how this motor works in stock before I started rebuild. Now I'm changing it to electrical fan, double 3" exhaust, cold air intake. I do not need more from this car.

 

I lost this game with heads. Just found a small crack on one exst valve seat.
No other option than to get other heads.
Looking to spend 400-600usd. What options do I have, vortec, l98?
Will L98 fit stock tbi intake? Whats the approx price for burned ecm chip?
Thanks.