6.5 vs 454 stories

[Arlie]

I'm interested to hear stories about 454 vs 6.5 driving, towing, mileage, durability.
Arlie

[Billman]

A modded 6.5 to a modded 454 is no comparison.

I've owned 3 carbureted 454's and none of them can hold a candle to my current 6.5.

Some people say the Vortec 454 is close. I'm not buying it.

Mileage empty is 8-10 compared to 14-16.

Towing mileage is 6-7 compared to 10-11. 454 towed 8-9000 lbs. 6.5 tows 11-12000 lbs.

No more overheating, cracked exhaust manifolds, ignition wires every year, stopping for fuel every 3 hrs and spinning the motor to 3300 rpm.

Complain all you want about a 6.5TD. I love it...

[Herman_Bolger]

WE recently sold a 7.4l gas truck. It was rebuilt.30 over,ported heads,towing cam,new throttle body,injectors,if it could be done for more power we did it. It ran perfect, lots of power, towed a 15,000lb load from seabrook tx to detroit mi. not a single problem. Would even maintain 55mph uphill.Of course like bill said got 6.5 mpg, melted a brand new set of wires,and had to stop for fuel every couple of hrs.I just purchased this 6.5TD, and am loving it already, can't wait to put all the goodies on this engine to see how it does. I know my 7.4's but i would not be in a big hurry to get another!!

[catmandoo]

i have a 78 3/4 4x4 with a 1970 454,not too hopped up,went with the stock high lift hyd cam,port matched the heads,.030 forged pistons,open chamber heads,and had a factory cast intake with q-jet and it worked pretty good ,eventually went with a wiend stealth intake and holley 780 and man did that wake it up.anyway went to a swap meet years ago ,buddy drove that pulling a cutlass without engine/trans and i had the 82 3/4 2wd sub 6.2 with banks pulling a loaded pickup box trailer.it was 130 miles to the swap meet,he could not keep up on the hills and had to stop on the way down and back for gas,when i got home i still had 2/3 of a tank.and yeah exhaust mani cracking plug wire eatin monsters.alright for a chevelle or camaro but leave the towin to the diesels.the truck finally took a dump and he wants to pull the engine and put in a pretty nice 74 3/4 4x4 he got from his brother,i'm still trying to get a 6.2 or 6.5 in there.

[Steve O.]

My brother just bought a low mileage '99 3/4 Sub with a 454. We're going to have a brotherly smack down at the Massachusetts Dyno Day on January 29. I can't wait to ruin his day...

Steve

[rjschoolcraft]

Where the 6.5TD really shines against a gas 454 is at high elevation... over 10,000 feet. The boost really makes up for the lower air density and the 454 really dogs. It is even noticeable at 7,000 feet. My dad had a 454 with Banks Power Pack in his 94 Newmar Kountry Star coach. It struggled above 7,000 feet.

[Keith Richards]

I had two 7.4l vortecs before I got the 6.5.I liked those motors,but never towed anything extremely heavy till I got the 6.5.To me,the power was very comparable,but fuel milage is no comparison.They (for me) were very strong,very reliable motors,but we are in a fuel crisis now and gas just plain sucks,compared to diesel.And I think my diesel should far outlive those motors.It's funny cause when I stomp on the pedal,this truck always reminds me of the 454's power wise,very responsive and torquey.I drove a 99 powerstroke recently and was not impressed with the power compared to my truck.I'm sure the intercooled powerstroke could tow much more than my truck,but seat of the pants feeling was not overly impressive,and it was not instantly responsive.My 6.5 is instantly responsive.