85 305 TPI.... under heavy acceleration and high rpm, heavy whitish smoke out the back. Heads were inspected and rebuilt when cam was replaced. All mods... cam replaced, new injectors, headers, cat removed, tranny rebuild 2400 stall, corvette servos/shift kit, k&n air filter, Pom modified for mods. Smoke is whitish, doesn’t smoke unless I smash the accelerator. Any help.

Have you lost any coolant from the overflow after it cools? Does the white smoke smell sweet?

I’ll check the coolant level tomorrow. As far as smell, was a trail behind me “going fast, speedo buried” stopped when I let off throttle. It has done this a couple times now.

Another post talked about transmission fluid potentially being the culprit? Can someone speak to this and the fix?

Sounds like high vacuum sucking oil down the guides... But you said the heads were rebuilt... Assuming new guides and seals....

Smoking after you let off the pedal?

No smoke when backing off pedal. Has happened every time in last few years when getting on the pedal.

if it would be burning trans fluid... I think that was in cars that had a vacuum mopdulator where the thing was leaking trans fluid into the vacuum line... I think 85 had 700rk....I dont think a 700r4 has that modulator?

[QUOTE=1989karr;6468963]if it would be burning trans fluid... I think that was in cars that had a vacuum mopdulator where the thing was leaking trans fluid into the vacuum line... I think 85 had 700rk....I dont think a 700r4 has that modulator?[/QUOTE

what would be the “Fix” here?

* Coolant in exhaust results in white smoke.
* Trans fluid could be white smoke but it would be from under car and linger for a while since the smoke is a result of a spill that is burning.
* Oil in the exhaust might appear white from driver seat but it's actually got a blue hue and smells like..... burning oil *cough*
* Incomplete fuel burn or running rich is black smoke.

Somebody with eyes and nose following behind you can settle the mystery.

[QUOTE=drathaar907;6468981]
its a simple fix, you just replace the modulator. I think it just bolts on / off and you attach the vacuum line

I think the Th350 has it but im not sure if the 700R4 has it. I don't recall though.

I did just add a pint of trans fluid. I was down a pint, periodically I have had to do this… seemingly the modulator could be the problem.

Modulator on a 700r4 ??

I guess I don’t know if the 700r4 has a modulator or not… anyone?

I don't THINK a 700r4 has any... does your car have the 700r4 or was it swapped to a th350? Im guessing 700 though.


If there's no modulator then you can scratch the trans fluid theory. My other guess would be bad rings since you rebuilt the top end / assuming its goo and if you're not getting over heat / losing coolant issues. Like Qwktrip said, oil appears white but you gotta look close / kinda long to see the blue.


If I recall the general diagnosis theory...

start up puff of smoke = valve seals
puff with acceleration = worn / stuck rings



I think the fastest thing to do would be to do the stick the finger up the tailpipe trick and see what kind of residue is in there... see if it;s got a little slick discharge on the inside of the tail pipe.... or if its kinda sooty / black kinda carbony


. You can also maybe have someone rev it a bit as you go out and sniff the exhaust a bit to see what it smells like even if no smoke comes out.