Not sure if I have the right form but here is my question. I have a 551ST which is my daily driver. The truck was restored awhile ago. The engine is very strong with 130 psi compression all 6. The rear end is stock but the 2nd owner put a 700r4 so his wife could drive it. The combo works great. In town fine and when I need to go on the freeway it goes into over drive .My question is what is a safe RPM for that engine if I need to take a trip with it.

If the engine is in good condition (no knocks, etc.) I would try to keep it under 3400 RPM for steady crusing. No reason it could not be put up to 4000 RPM for shorter bursts and in indirect gears.
Truck engines transmit a lot of noise due to the large fan blade they use, the small cabin. and no cloth material in the cabin to absorb noise.
Just laying carpet on the floor over the rubber mat helps to absorb noise.

if he is at 3400 rpm in 4th gear with a 700R4, he is motoring.

my 2003 S10 extreme with 3.42 gears at 60 mph is 2200--2400, get it up around 3400, its making driveline noises from that 2 piece driveshaft.

mike

They drive faster in Calfornia

after running down to florida and back 4 months ago on hwy 75 interstate, they were running in excess of 80 mph, in packs freight training . Louisiana, Alabama, florida all running 75 + easily.

Same thing last spring in the Virginia NC SC and into Georgia on a trip. Vermont New Hampshire in the morning they were running 90 mph

If your in a vintage car, better be to the right so you don't get run over.

mike

Thanks for all the info.. It is still a 55 1st pickup with stock suspension so running at 60 to 65 is all I want to do and you are right sometimes in calif. on the freeways it does feel like the 1st lap talledega and some one is bump drafting you Thanks again

A properly balanced set of wheels and tires, with correct alignment will give you a more confident feel.

I strongly suggest the use of RADIAL TIRES..........touring type, soft sidewalls, grippy rubber, run well in rain, stops better.

You will never run bias ply again. You turn the wheel, car goes where you want it too, not like Bias ply that has you wandering all over the place following the ruts in the roads.

Believe the leader in vintage looking tires is coker

make sure your steering box is up to snuff with almost no play in the wheel.

happy motoring

mike