[Chevy 350 Fan]

[QUOTE=Gromit;7450387]Idle is way too high in my opinion - need to do whatever it takes to fix that first.. Stock idle is more like 580 to 650 for my TH350 in a 290 HP 350 Cubic Inch V8 with a stock Corvette HP cam (but sounds like you have even more HP than that) - But at least your extreme high idle is affecting your vacuum levels which is then affecting your trans valve body logic. 1500 RPM is well into the jets and the butterflies are completely out of the idle circuit, so vaccum is lower than it should be at idle.

Then if those steps don't fix things I would worry about how the converter was bolted up to your new flexplate.. That install is kind of tricky for me anyway...As in which bolt goes in first and assuming you get the right one in first did you torque that one all the way to spec before putting the other bolts in or did you install all bolts finger tight first and then tighten the rest sequentially? (some bolt holes are slotted and one is meant to be dead on). Did you use a torque wrench to cinch the converter to the flex plate?

Why did it catch on fire anyway?

Next (or even first) I would worry about the trans fluid level - It needs to be checked with the engine warmed up, engine running, select each dear position for 15 seconds, then finally in Drive, Parking brake on and idle speed at spec of course.. and you need to have the correct dipstick - then you can't have any extra fluid in the trans.. that will just foam it all up.. The fluid level needs to be just right and it is only one pint between low and high on the dipstick - not a quart as many people assume.. If it is above full get a $6 drain plug kit and drill the 1/2" hole in your pan in the flat spot provided..

Actually I wouldn't spin that motor up again until I pulled the transmission pan to check for any extra parts as one previous poster so wisely pointed out..

Why would the idle speed matter? My vacuum is going to be lower anyways because of my cam. I thought the modulator just affects when it upshift not going into gear period. My plan was to adjust it to shift earlier to compensate for the lower vacuum. Now I did replace the dipstick because the old one was burnt and the rubber seal at the top was burnt so every time you messed with it little bits of burnt rubber would go down the dipstick. I think I checked to be sure that the levels were the same. I ordered it from AZ and they said it would fit my tuck. If the fluid was low I don't know why it would only affect drive. and it would have to be REALLY low for it not to go into gear. I had a blazer with a 700R4 that they guy only put a quart of fluid into it consequently, one minute reverse worked the next it didn't. He thought it had a broken drive shell. Added, fluid it worked fine. point is it would need to be really low. I added additional fluid, but it made no difference. As to why it caught on fire I think the culprit was a brake line connector that was rubbing on the header. it wore all the way through so I think brake fluid caught on fire and it went down hill from there.