V8Astro Captain

iTrader: (1)

I ran the engine up to 4000 rpm in 3rd and it seemed like it hit "the wall" that I've read about in the archives. As you can imagine at 90+ mph my van has alot of wind resistance so I don't really know if it's valve float or it getting to the point where the engine is over the power peak and the wind is trying its hardest to stop me.

SO...does is valve float usually accompanied by any clattering? I have 105# springs on my 196/206 @ .050" .431/.451 cam. The valve lash is set to 1/2 turn.

TIA

jcb999

Most 350s even with the stock 195-205 cam will pull 5000 n/p.
I don't think thats ur prob.

Fuel flow?

V8Astro Captain

iTrader: (1)

That's my gut feeling. My OEM 120k miles V6 fuel pump probably doesn't like me anymore. On Monday I'm gonna get some stuff to plumb in a fuel pressure gauge and watch the puppy.

Are the TBI and TPI fuel pumps physically the same? I found a hi-flow TPI pump in Jegs...but no TBI pump. If they are the same I plan on running the TPI pump with a 3-port return regulator. Do-able?

Vader

Cap,

My old Astro would do 95+ with the original 262 (or at least somewhere areound there - since it's hard to guess with an 85 MPH speedo). Your V-8 shouldn't be held back by aerodymanic drag.

Valve float usually doesn't create any noise unless the valves are being closed by the pistons. You can get a little popping or backfire in the intake with float, but not always.

I think you're on the right track with the fuel pressure testing. If that doesn't reveal anything substantial, its on to the ignition.

As for the pumps, they are not the same, but you should be able to get a TPI pump to fit on the TBI assembly without any problems. The lengths are close enough and the difference can be made up in the hose adapter length if necessary. The extra diameter shouldn't create a c;earance problem.

V8Astro Captain

iTrader: (1)

I also remembered that I had the max spark adv. limited to 3500 rpm. That was for the old cam, don't ask...it just worked better that way. So I set it back to the stock 4200 rpm...I'll have to go try it.

I still plan on getting a fuel pressure guage tomorrow.

Guest

About the only sound I can think of is a change in the exhaust note. The power will go completely flat when it happens, so you let off and then it recovers again. Dont think thats what yours is doing, really too low of an RPM.