Sudden Power Loss (opinions)

[Mike69cuda]

Have you checked the muffler bearings?

 

[archerandethansdad]

Yep all good.

 

[AJ/FormS]

Well then we seem to be running out of things to check, that do both powerloss and a temperature change. Maybe you want to check your exhaust system for back-pressure.
EDIT
I do this by installing an 3/16 x 8 inch brakeline brazed into the exhaust pipe up into one leg of the Y-pipe. To that I attach a length of hose that allows a low-pressure gauge to be routed into the front seat area. Then I take for a ride. I find a long straight deserted road, get her up into second gear and give her a workout...... while watching the gauge.
Ideally, I want to see ZERO back-pressure, lol.
Typically I see 1.5 to 2.5 psi on a decent system, maybe 3.0 at most.
If it goes over 4psi, I want to know what's plugged. This might require moving the tap two or three times.
When finished, I shorten the pipes so they can't snag on stuff, but leave them in, and braze them shut.

 

[archerandethansdad]

I will check manifold temps today and report back any odd findings. I haven't checked brakes yet this could be the culprit.

 

[archerandethansdad]

So i just checked temps across the manifolds 1 390ish, 3&5 450's, 7 420's, 2 400, 4&6 470's, 8 380ish. Obviously it's tough with cast iron manifolds as the temps will creep throughout the entire thing but within an inch of the head that's what i was getting. Sound normal-ish? At idle not moving it will stay between 180-190. On hot summer days it may creep up as well. I did go from a 195 tire to a 225 but the way it would smoke'em before i don't see that being the issue. Could be wrong.

 

[AJ/FormS]

Oh boy!
Well maybe; what are the tire heights, or the exact sizes?
And did both tires spin before?
a 195/70-14 is about 24.7 tall
a 225/75-15 is about 28.3 tall
for a difference of 14.5% which would be like going from 3.23s, to 2.76s.... so I mean it's possible.

BTW;
If only one wheel spun; and you have an open differential, this action makes the tire spin at twice the indicated speed on the Speedo. This often cooks the gear oil and welds the spiders to the crosspin, making it a poor-man's posi.
But, you will lose the differential action which will suck power on every turn, and; if the two rear tires are not equal in roll-out, this will suck power too, and one of them is gonna wear out prematurely.

 

[archerandethansdad]

Oh boy!
Well maybe; what are the tire heights, or the exact sizes?
And did both tires spin before?
a 195/70-14 is about 24.7 tall
a 225/75-15 is about 28.3 tall
for a difference of 14.5% which would be like going from 3.23s, to 2.76s.... so I mean it's possible.

BTW;
If only one wheel spun; and you have an open differential, this action makes the tire spin at twice the indicated speed on the Speedo. This often cooks the gear oil and welds the spiders to the crosspin, making it a poor-man's posi.
But, you will lose the differential action which will suck power on every turn, and; if the two rear tires are not equal in roll-out, this will suck power too, and one of them is gonna wear out prematurely.

So they are 225/55/15's and it is a suregrip rear end. I was fortunate enough to get the actual order sheet from the original buyer.

 

[AJ/FormS]

they are 225/55/15's and it is a suregrip rear end.

Ok well then 225/55-15s math to 24.7; and so the size-difference might be a wash.
And as for the sure grip, if it is the cone type, then after all these years, it may not be working anymore, and it only has 2 spiders. So that story is still plausible.

 

[archerandethansdad]

Ok well then 225/55-15s math to 24.7; and so the size-difference might be a wash.
And as for the sure grip, if it is the cone type, then after all these years, it may not be working anymore, and it only has 2 spiders. So that story is still plausible.

Before this happened it left two beautiful black lines. But i can check by jacking the rear and spinning.

 

[Inertia]

If you haven't checked the rockers/pushrods yet, - I'd start there .

 

[George Jets]

Sitting there having to power brake to get your tires to break free is not real smart in the first place.

Abuse your equipment, expect things to go wrong.

Tranny overheated and it's all down hill from there.

 

[archerandethansdad]

Sitting there having to power brake to get your tires to break free is not real smart in the first place.

Abuse your equipment, expect things to go wrong.

Tranny overheated and it's all down hill from there.

Thanks dad, but it sure is fun.

 

[AJ/FormS]

Thanks dad, but it sure is fun.

I like your sense of humor. You keep getting scolded, but you take it, and what's more; you give back humor. keep it up.