How Would You Build a JY "Hot Rod?"

[Russell]

Chevy seems to have a policy of making weird decisions with downsized V8s. First it was the 307 - OK as a truck motor, I guess. Then there was the 262, built for the '70s, but couldn't pass '70s emissions rules like the 350. Next, they de-bored the 350 to make the 305 and put it in a Camaro even though the engine really didn't like to rev and would have been happier in a truck. Then somebody got the idea to revive the 4.3 liter size for an LT1 variant that has nearly been forgotten. Then the latest weird choice was to destroke the 5.3 into an engine that's happiest at 5000-6000 RPM bone stock... and make that the base engine for U-haul moving vans and other heavy trucks. I don't get it...

Never driven a moving van, but the people that do more than likely don't need a lot of power, they should take it slow not sure what gear those things have but having somthsome that can spin high rpm a good idea.

The one 4.8 truck I have driven was a 2wd Silverado. I thought it was really peppy. The only thing I have driven with the 5.3 is a suburban. I would say that the Silverado would be faster, but it's also lighter?

[RockJustRock]

This is going to sound familiar, maybe, but...

MN12 Thunderbird or Cougar (think the 90's models). Pumpkin and lower control arms from a similar vintage Mark VIII (IRS 8.8, aluminum). Cheap quick and easy way to power is to drop in a 5.0 that's been gone over, speed parts are pretty easy to find used, early versions of this model TBird had the 5.0, so computers, brackets, etc... are not too difficult to find. Brakes can be upgraded with Cobra calipers and rotors. Transmissions get tricky, due to hydraulic clutch requirement, but they are still out there. They handle great and are comfy to cruise in. When they came out they were hefty, but compared to modern cars not so much. Aero is slicker than snot on a doorknob. People practically give them away used.

I like that platform because it shouts "LOW". Those window sills do it. Rented a few in the 80s and on the freeways even next to Vettes they felt low. The hobby hated them because of no factory V8s, but now it is a bolt in. Best sleeper platform of the period.

[RockJustRock]

Chevy seems to have a policy of making weird decisions with downsized V8s. First it was the 307 - OK as a truck motor, I guess. Then there was the 262, built for the '70s, but couldn't pass '70s emissions rules like the 350. Next, they de-bored the 350 to make the 305 and put it in a Camaro even though the engine really didn't like to rev and would have been happier in a truck. Then somebody got the idea to revive the 4.3 liter size for an LT1 variant that has nearly been forgotten. Then the latest weird choice was to destroke the 5.3 into an engine that's happiest at 5000-6000 RPM bone stock... and make that the base engine for U-haul moving vans and other heavy trucks. I don't get it...

In those days Detroit had Engineering departments that were delinquent in mathematics and science. So many really BAD engine decisions. The science and math were there, bore/stroke/rod length ratios, piston velocities, chamber design, runner volume to power curve RPM range, exhaust efficiency and overlap scavenging, but it came down to what can the foundry crank out with ease and what will look good on the option list. And beans. Bean counters counting beans.

[Gateclyve Photographic]

Never driven a moving van, but the people that do more than likely don't need a lot of power, they should take it slow not sure what gear those things have but having somthsome that can spin high rpm a good idea.

The one 4.8 truck I have driven was a 2wd Silverado. I thought it was really peppy. The only thing I have driven with the 5.3 is a suburban. I would say that the Silverado would be faster, but it's also lighter?

U-Haul and other fleet buyers like the idea of cheap.

I strongly suspect the various SBC and LS downsizings are a function of what is cheap to machine on existing tooling.

Several brands experimented with downsized OHV V8s during the early days of CAFE . . . 260 Olds, 301 Pontiac. Cadillac HT4100, Ford 255 . . . None particularly successful from a hot rodder's point of view. All eventually replaced with either V6s or larger V8s.

[Russell]

What makes a 4.8 cheaper than a 5.3?

[RockJustRock]

IMHO if the racing bodies would lower displacement limits we'd see some bangin' new small V8s, maybe even in production cars. NHRA Pro classes from 500 CI to 5 liters. Nascar to even smaller because 5.8 is already so small. Sucks that NHRA RPM limits Pro Stock. Killed the Hemis there.

[RockJustRock]

What makes a 4.8 cheaper than a 5.3?

CAFE (ducking!)

[SuperBuickGuy]

What makes a 4.8 cheaper than a 5.3?

displacement doesn't always make it the best motor. Example, the guys that put a 632 ci BBC in their Corvette....why? I get 632 in a Cadillac or a truck - but a car? GM spends more time (as well as Ford) trying to convince the buying public that big cubic inches don't mean better performance..... the tuner world has embraced the 5.3 and 4.8 first because they're cheap but then soon they realized that a 6.0 in a 240sx was a waste of money....

and I'll put my pocketbook there as well. I could build a SBC 427 and my friend is putting a SBC 427 in his Corvette. We'll never race because my BB big bore/short stroke 427 will take his lunch money every day and twice on Sunday.

[Matt Cramer]

U-Haul and other fleet buyers like the idea of cheap.

I strongly suspect the various SBC and LS downsizings are a function of what is cheap to machine on existing tooling.

Several brands experimented with downsized OHV V8s during the early days of CAFE . . . 260 Olds, 301 Pontiac. Cadillac HT4100, Ford 255 . . . None particularly successful from a hot rodder's point of view. All eventually replaced with either V6s or larger V8s.

Yes, that's usually the idea with the downsized engines - easy to make on existing tooling. Apparently the 4.8 was supposed to get better mileage, but didn't pull that off in the real world. The "it was a cheap change to make" part I can certainly understand - the weird part is what platforms the engines wound up in.

[squirrel]

also carmakers like to have a few options that cost them the same to make, but bring in extra $$$ for the "premium" version. So having a 4.8 standard, and charging an extra $500 or so for the 5.3, is a tidy little profit center