L79 vs BB

[William F.]

Anyone have opinion,"race results", or data regarding which would have better quarter mile times?;'67 L79 with wide ratio and 3.70 gearing or "67 390 hp BB with wide ratio and 3:08 gears-both stock, in good mechanical shape, and both with factory side pipes?

[Gene M.]

Re: L79 vs BB

"Grumpy" took on everything back in the day with an L79 sb. Stock is kinda subjective at best...........!

Tires and driver will also have a bearing on the out come.

[Edward J.]

Re: L79 vs BB

Bill, the Small block short stroke engine was a quick rever and generally had the advantage in the first 2/3ths of the qtr. mile, but the longer stroke would catch you at the end. there are to many other varaibles that come into play also. The 308's maybe the only thing holding the big block back.

You should be able to find some data on the internet, I would gander to say the small block was a low 14 sec. car as the block block car were 13.5 sec. cars. this is with the belted tires of the era.

[Bill M.]

Re: L79 vs BB

Car Life July 1969 did a drag test on:

'69 L79 M21 4.11 ... 14.55 @ 98
'69 L36 M20 3.08 ... 15.02 @ 93

The M21 4.11 is the same as a M20 3.55 in 1st, 2nd, 3rd

[Robert R.]

Re: L79 vs BB

...so why all the "big to do" on Big Blocks?
Maybe info like this will return all those BB's back to or even remade as L79s
My '67 L79 Coupe used to scare my then fiance and now bride of 29 years.
Bob

[William L.]

Re: L79 vs BB

Anyone have opinion,"race results", or data regarding which would have better quarter mile times?;'67 L79 with wide ratio and 3.70 gearing or "67 390 hp BB with wide ratio and 3:08 gears-both stock, in good mechanical shape, and both with factory side pipes?

Why are you penalizing the B/B with 3:08 gears? If both car's had 3:70's and the same tires (Cheater Slicks). I think the B/B would catch the S/B at the 1000 ft mark and win by about 2 ten's My ET guess 13.5 to a 13.7 and that may be to fast???

[Paul H.]

Re: L79 vs BB

I have a 65 327/350 3:55 4 speed and also a 68 427/390, turbo 400, 3:08. The big block will walk away from the L79 with ease especially once you are up to speed. The L36 makes alot of low end torque and it revs. Nice motors. Both are basically stock.

[Edward J.]

Re: L79 vs BB

Why are you penalizing the B/B with 3:08 gears? If both car's had 3:70's and the same tires (Cheater Slicks). I think the B/B would catch the S/B at the 1000 ft mark and win by about 2 ten's My ET guess 13.5 to a 13.7 and that may be to fast???

Bill, back in the day I use to be at the drag strip every weekend, racing back then I was into mopars the problem with the big block spun the tires just to much which killed the ET ,But at the end of the qtr. the MPH was higher , the 308 ratio may have helped a little with off the line tire spin. a high ratio such as a 370 ratio would be a harder to keep the tires planted on the ground.

[Gene M.]

Re: L79 vs BB

Anyone have opinion,"race results", or data regarding which would have better quarter mile times?;'67 L79 with wide ratio and 3.70 gearing or "67 390 hp BB with wide ratio and 3:08 gears-both stock, in good mechanical shape, and both with factory side pipes?

Bill,
I could be wrong (going on memory) but the 3.70 gears required a close ratio tranny.

[William L.]

Re: L79 vs BB

Bill, back in the day I use to be at the drag strip every weekend, racing back then I was into mopars the problem with the big block spun the tires just to much which killed the ET ,But at the end of the qtr. the MPH was higher , the 308 ratio may have helped a little with off the line tire spin. a high ratio such as a 370 ratio would be a harder to keep the tires planted on the ground.

Back in my day I also did a little drag racing. It may be semantics but we called 3,08, 3.36 a highway or tall gear and 4.11, 4.56 a low gear. I think mopar had a 5 something rear gear. I know the guy I helped, when the track was lose and had no or little Bite we lowered gear ratio from a 4.11 to a 5.13.
I had a buddy that bought a 63 fuelie that had a 3.08 in it and he could never control the tire speed off the line. It would ether light the tires or bough of the line and if I remember right he almost always went through the lights in 3ed gear.

[Michael H.]

Re: L79 vs BB

...so why all the "big to do" on Big Blocks?
Bob

There's quite a difference between a 390 HP and a 425/435 HP 427. That's a whole difference game.

A good friend had a red/red 67 350 HP conv in the 60's and he regularly beat a guy with a 67 390 HP.

In my opinion, a 350 HP 327 is one of the best all around production engines anyone built in the 60's.

For some unexplained reason, there were a few pretty quick 390 HP cars but most that I remember from that time were not.

[William F.]

Re: L79 vs BB

You're absolutely correct about 3.70 with close ratio but actual L79 car in question did come with a close ratio but now actually has a Tremec 5 speed (original 4-speed in box); just didn't want to complicate issue but I know the tremec gear ratios would make some difference.

[Bill M.]

Re: L79 vs BB

There's quite a difference between a 390 HP and a 425/435 HP 427. That's a whole difference game.

Car Life ran an L71 (427/435) in the above-referenced test:

'69 L71 M21 4.11 ... 13.94 @ 106
'69 L36 M20 3.08 ... 15.02 @ 93
'69 L79 M21 4.11 ... 14.55 @ 98

[Tom P.]

Re: L79 vs BB

Re-read Gene's comments at the top.
Completely torn down, rebuilt and "tweaked", optimal gearing and tires, an L79 in the hands of the "right" driver is hard to beat.
And then there are those of us who just CANNOT tolerate a stock SB. We just GOTTA mess with it! The smallest SB I own is a 388 (.060 over/3.75 stroke).
I shock a lot of folks with the 383 in this rusted POS.

[Jim B.]

Re: L79 vs BB

Back in the day, I raced my 68 L79 with 3:70 rear and Close ratio Transmission. It generally was faster (high 13 to very low 14) than the lower HP big blocks. The 390 HP was no problem, the 400hp was a good race. Anything higher was a problem for my L79 but not much of one.
I remember that the big blocks had a lot of trouble with weight transfer on start and they really lifted their front end off the line. The L79 was a high rev engine and generally ran away at the end.
Back in the day though you really didn't see many corvettes at the strip. They ran in a whole different class (SP) under NHRA rules so many of the racers went to chevelles and camaros.
I also found that the big blocks did not do so well under SCCA racing unless you did some hefty modifications. The iron big block made the car unbalanced for the stock suspension. The L79 was a lot more fun on the twisty road for me.