1970 ZR1

[Mystic ZR-1]

Originally Posted by BigJohn

Kind of like my 440 GTX with 370 hp.

Oh ya, it only has one Cam!

But I still love to drive it!

What your GTX lacks in cams, it makes up for in cubes!
Rule #1:there's no replacement for displacement...
4 cams and displacement? LOOK OUT!
In the case of your '38. 6 in a row makes ETs low...

[BigJohn]

Originally Posted by FU

Runs like a 400+ rwhp car and is a light weight high rever. That 350 engine comes live at 5K.



440 GTX is torque monster and a porker. The first gen. LT5 with a good set of rear tires will clean the 440's clock. Hook it up and she's gone.
I had a 440+6 Challenger back in the day, and used it very well.

Cool, I have owned my GTX for over Forty years.
I know it can't beat my ZR-1 or any of my other 500+ and 650+ hp cars.
My little SSR will do 128 mph in the quart mile and it's weight is about 4800 lbs.

[cuisinartvette]

3.08 gear with that motor is that possible?
seems mismatched to me.

I love the old Gen 1 sbc with solid cams dont care what anyone says. Had a 70 Z/28 with a rowdier cam and headwork couldnt kill that thing used to beat it to death and was a daily driver to boot. impound yard finally destroyed it. Love the twin cam LT5 motor but my current Gen 1 motor would probably clean just about any new cars clock, they aint dead yet!

[USAZR1]

Originally Posted by cuisinartvette

3.08 gear with that motor is that possible?
seems mismatched to me.

I noticed that,too. Someone on here has one of those cars and it's got a 4.56 cog in back. Now,that's more like it for that combo.

[Hog]

Originally Posted by FU

Runs like a 400+ rwhp car and is a light weight high rever. That 350 engine comes live at 5K.

Just like the 1964-65 L76 carb and L84 fuel injected 327's. The L76 doesnt have a whole lot of off idle torque, but once the tach sweeps past 4500rpm at WOT, she pulls very nicely. The "Fuelie" engines were even worse(better-lol) due to their tunnel ram configuration. The 365hp L76 and 375hp L84 327's are the same engine save for the induction.

A L76/L84 longblock with dual 4 barrel carbs, with open headers in a 57 Chev Sports Sedam(2 door hardtop) with a 4 speed manual trans, and 5.13 gearing on 60's slick tire technology was good for 14 with second ET's. Then Sunday nights, the slicks and 5.13's came off, street tires, 3.55's went in and the mufflers got hooked back up for daily driving duties.

Actual car


Actual ad of car


Same car in 1995 during a car show that Mom And Dad organized. I was on leave and made it back for the show. Car was trailered.


Same car (on trailer)





Factory Rating of GEN 1 SBC's
L-76 327 V8 365 bhp @ 6200 rpm, 350 lb-ft @ 3400 rpm 4bbl carb
L-84 327 V8 375 bhp @ 6200 rpm, 350 lb-ft @ 4600 rpm MFI (hiest stock gross hp rating of all GEN 1 SBC engines
LT-1 350 V8 370hp @ 6000rpm, 380 lb/ft torque @ 4000rpm 4 bbl carb

Modern dyno testing using the same longblocks carb and Ramjet injection were both fully tuned after installation:
L-76
355 hp @ 5,700 rpm,366 lb-ft of torque at 4,100 rpm 4bbl carb A modern cam Comp Cams XS274S (0.501/0.510 lift/ 236°/242° duration @ 0.050" lift) tested and produced an extra 20hp/20 lb/ft torque over the original Duntov camshaft(0.484"/0.484" lift, 254°/254°duration@0.050" lift, 114°LSA
L84
365hp @ 5600rpm/362lb/ft torque @ 4400rpm Ramjet Mechanical Fuel Injection


The following engine dyno testing, not related to the above
1970 GEN 1 SBC-2nd highest gross power rating of all GEN 1 SBC's
LT-1 353 hp @ 5,600 rpm, 392lb-ft at 4,100rpm
0.459"/0.485" 242°/254° Solid Flat Tappet
Holley 3310 4V 780cfm 4 bbl carb


1996 GEN 2 SBC rated at 300 sae net hp @ 5000rpm/340lb/ft @ 4000rpm
LT1 351 hp @ 5,700 rpm, 379lb-ft at 3,900rpm
0.450/0.460 202°/207° LSA 116° Hydraulic Roller Tappet
Dual 48mm-630cfm

There is of course no comparison of the solid tappet, lopey idle and throttle jazzing during clucth application to the smooth hydraulic roller cam idle and ability to apply the clutch from an idle.
I know which one is more visceral, more mechanical and stimulates the senses the most. Each has it's place depending upon what one is trying to accompish.

GEN 1 through GEN 5 now, with a Chev 4 cammer thrown in the mix. Such technology, such evolution while at the same time, in some respects, remaining the same.
Nothing like these Chevrolet V8 engines.

[BigJohn]

Nice!!!!!

[ZRXMAX]

[QUOTE=cuisinartvette;194397]3.08 gear with that motor is that possible?
seems mismatched to me.QUOTE]

That gear does seem a bit tall... however, if low end torque is absent then the clutch will suffer over time.

Keep in mind your only 1 to 1 in 4th gear and for those that have run 4.56s on the street with a 4 speed... well... you know its no fun driving a 100 miles to go some where as you cruise at 55 mph and 3 grand on the tach... or something like that.

However, when the slicks are sticky and the clutch dumping traction factor is high... deep gears rule!