370hp LT1 vs 355hp ZZ4
Thread Starter
Racer
Joined: Jan 2006
Posts: 395
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From: Orange massachusettes
370hp LT1 vs 355hp ZZ4
I was looking thru the specs for the 1970 Lti and was wondering if it really makes more power than the ZZ4? Anybody out there ever swap one for the other, and or drive both and have a opinion of which is better? Also does anyone know roughly how quick 72 vette would be with ZZ4, 4spd, and 3.55"s ? I'm not sure if old road tests of LT1's or 350/350's are accurate way of determining real world performance of ZZ4's. Would really like to know 0-60 mph and 1/4 mile times.
Le Mans Master
Joined: May 2006
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From: League City Tx
I would guess that the ZZ4 is better in the low to midrange but the LT1 would rip it up top. We have a ZZ4 in our 59' and its pretty weak to be honest with you. Its done by 5200rpms. I guess it would depend on the weight of the car and gearing. The heads on the ZZ4 are the bottleneck. I would think a well tuned ZZ4 would go some 13.80s in a 72 with some decent gearing, maybe quicker if its an auto with a stall converter.
Race Director
Joined: Dec 1999
Posts: 11,094
Likes: 990
From: Sierra Foothills CA
Originally Posted by ajrothm
I would guess that the ZZ4 is better in the low to midrange but the LT1 would rip it up top. We have a ZZ4 in our 59' and its pretty weak to be honest with you. Its done by 5200rpms. I guess it would depend on the weight of the car and gearing. The heads on the ZZ4 are the bottleneck. I would think a well tuned ZZ4 would go some 13.80s in a 72 with some decent gearing, maybe quicker if its an auto with a stall converter.
I drove a buddy's 69 Camaro w/ the ZZ4 and it had nice crisp throttle response right off the bottom w/ really good torque in the mid range but didn't have the strong top end of my 70 Z28's LT1. Both cars have headers & IMO both motors need them. Either would be a good choice- street manners are better w/ the ZZ4 but the LT1 has a very gratifying, intense hard revving charge in upper RPMs.
Le Mans Master
Joined: Apr 2006
Posts: 5,403
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yrs ago when you could still buy the parts over the chevy counter
I built an exact copy of the LT1 and put it in my 66 with M/21
4.11 rear. The LT1 engine has nothing below 3400 pulls good to around
6200. With a 4 speed and 3.55 gears buy the 385. two yrs ago I drove
a good freind of mines all original 70 LT1, M21, 3.73 gears, still the
same nothing below 3400.
I built an exact copy of the LT1 and put it in my 66 with M/21
4.11 rear. The LT1 engine has nothing below 3400 pulls good to around
6200. With a 4 speed and 3.55 gears buy the 385. two yrs ago I drove
a good freind of mines all original 70 LT1, M21, 3.73 gears, still the
same nothing below 3400.
Last edited by Little Mouse; Aug 22, 2006 at 06:09 PM.
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Le Mans Master
Joined: May 2006
Posts: 9,993
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From: League City Tx
Ya I think the LT1 cam has something like 250* duration at .050 which is just freakin ridiculous. No wonder why they only ran 14s.
72LT1, I think you would run better with the FB 385. Eventhough the ZZ4 may have a little more way down low, after 3k the fastburn is going to rip up to 6k. With 3.55s you will be ok. ALTHOUGH, I would go with a ZZ383 if you can swing the extra $1k. Then you will have more power all the way through and enough beans to get it into the 12s.
Our 59' with the ZZ4 has a M22 and a 9" ford with 4.11s. It dynoed 250-263rwhp depending on the pull. Granted the 9" ford is heavy and kills some HP, this car just does not accelerate that well to be honest. It runs well and is reliable as a stone but....with the 2.20 1st gear, it will barely spin the 215/70 BFGs from a slow roll in 1st. I bet it would barely run low 14s at best.
72LT1, I think you would run better with the FB 385. Eventhough the ZZ4 may have a little more way down low, after 3k the fastburn is going to rip up to 6k. With 3.55s you will be ok. ALTHOUGH, I would go with a ZZ383 if you can swing the extra $1k. Then you will have more power all the way through and enough beans to get it into the 12s.
Our 59' with the ZZ4 has a M22 and a 9" ford with 4.11s. It dynoed 250-263rwhp depending on the pull. Granted the 9" ford is heavy and kills some HP, this car just does not accelerate that well to be honest. It runs well and is reliable as a stone but....with the 2.20 1st gear, it will barely spin the 215/70 BFGs from a slow roll in 1st. I bet it would barely run low 14s at best.
Le Mans Master
Joined: Apr 2006
Posts: 5,403
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Originally Posted by 72 LT1
little mouse, do you think the Fastburn 385 will still pull hard at lower revs, and how much rpm are you gaining on top compared to the ZZ4?
I would choose the higher torque ZZ/4 to work with the bigger
rpm drops of the wide ratio trans, if you have the M/21 I would
go with the 385 HP. Both of these engines will have far more torque
down low then the old narrow power band LT1 motors. Well being the
HP fanatic that I'am I would probably have to have the 385HP.
Last edited by Little Mouse; Aug 22, 2006 at 07:45 PM.
Racer
Joined: May 2006
Posts: 268
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From: Farmington Hills Michigan
Originally Posted by BKbroiler
As I recall, the 1970 hp ratings were in gross terms while the current ratings are net, so you have to reduce the LT1 by maybe 10% to compare.
Does anyone know the whole story?
Burning Brakes
Joined: May 2004
Posts: 1,100
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From: belle plaine ks
This was the LT1, a high horsepower version of the 350 c.i. small block V-8. Using a solid lifter camshaft and an 11.00:1 compression ratio, the 350 was rated at 370hp The LT1 could be had only with the four-speed manual transmission.
Team Owner
Joined: Jul 1999
Posts: 26,545
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From: Huntersville NC
The 1970 LT-1 was rated at 370 hp - yes, that was a gross hp rating at the flywheel. But crate engines like the ZZ4 are also rated gross at the flywheel. Crate engines that are not original equipment installed in cars are rated gross. (How would you rate them net, btw... what exhaust and accessories would you attach?) However, crate engines that also come installed as original equipment in cars generally retain their net installed rating. Makes it a little hard to compare, for example the 502/502 bigblock is rated at 502 horsepower, but that is GROSS. The new LS7 is available as a crate engine, rated at 505 hp, same as it comes in the ZO6, but that is NET. So which one is putting out more hp? This is not a trick question, obviously the LS7.
I puzzled over this dilemma (crate engine hp ratings) for some time, and did quite a bit of research. If I got anything wrong.... let me know!
I puzzled over this dilemma (crate engine hp ratings) for some time, and did quite a bit of research. If I got anything wrong.... let me know!
Le Mans Master
Joined: May 2006
Posts: 9,993
Likes: 1,136
From: League City Tx
PRNDL, you are exactly right on the gross ratings. Crate motors are gross rated. Even custom built crate motors from engine shops are dynoed and rated with shop headers, electric water pump, no fan, no PS pump or alternator.
Thats why I get a kick out of seeing old muscle cars dynoed on a chasis dyno. The looks on the owner's faces is classic.
Basically, trap speed is a good indicator of HP. Yes there are many variables that can affect it but for the most part, that is a key indicator.
An original LT car on average ran 100 mph in the 1/4. In a 3300lb car that equates to 250-270rwhp.
Although last weekend my 3700lb TA only ran 110.62 with 380rwhp and it should have been in the 114-115 range. The heat, crappy shifting T56 tranny and a big cam with no low end tq were all killing the mph. I was only going 87mph in the 1/8 which is horrible.
Chasis dynos are a good tool for tuning and testing, then hit the strip with em.
Thats why I get a kick out of seeing old muscle cars dynoed on a chasis dyno. The looks on the owner's faces is classic.
Basically, trap speed is a good indicator of HP. Yes there are many variables that can affect it but for the most part, that is a key indicator.
An original LT car on average ran 100 mph in the 1/4. In a 3300lb car that equates to 250-270rwhp.
Although last weekend my 3700lb TA only ran 110.62 with 380rwhp and it should have been in the 114-115 range. The heat, crappy shifting T56 tranny and a big cam with no low end tq were all killing the mph. I was only going 87mph in the 1/8 which is horrible.
Chasis dynos are a good tool for tuning and testing, then hit the strip with em.
Racer
Joined: Dec 2005
Posts: 325
Likes: 0
From: Partlow VA
You may want to look at the Yearone crate motor?
Engine Specifications:
·Horsepower- 400+
·Torque- 400+ ft/lbs
·Compression ratio- 9.5:1
·Dyno-tested: Yes, includes harmonic balancer and flexplate
·Dyno sheet: Included with engine's output
·Vacuum produced: 12hg @ 800RPM
·Recommended fuel- 92 octane
·Max recommended RPM- 6000
·Block- Seasoned 4-bolt iron
·Crankshaft- Nodular iron
·Pistons- Hypereutectic
·Connecting rods- Powdered metal
·Camshaft- Hydraulic roller
·Valve lift:.520"
·Duration @ .050" (int/exh): 218deg/228deg
·Rocker arms- 1.6:1 ratio
·Cylinder heads- Ported Vortec
·Valves- Stainless steel 2.02 int/1.60 exh
·Valve springs: Heavy duty
·Bore x Stroke- 4.030" x 3.48"
·Intake manifold- Dual-plane aluminum
·Oil pan, timing cover, valve covers included
·Engine fasteners: High tensile strength
·Warranty- 12 month/12,000 mi
Engine Specifications:
·Horsepower- 400+
·Torque- 400+ ft/lbs
·Compression ratio- 9.5:1
·Dyno-tested: Yes, includes harmonic balancer and flexplate
·Dyno sheet: Included with engine's output
·Vacuum produced: 12hg @ 800RPM
·Recommended fuel- 92 octane
·Max recommended RPM- 6000
·Block- Seasoned 4-bolt iron
·Crankshaft- Nodular iron
·Pistons- Hypereutectic
·Connecting rods- Powdered metal
·Camshaft- Hydraulic roller
·Valve lift:.520"
·Duration @ .050" (int/exh): 218deg/228deg
·Rocker arms- 1.6:1 ratio
·Cylinder heads- Ported Vortec
·Valves- Stainless steel 2.02 int/1.60 exh
·Valve springs: Heavy duty
·Bore x Stroke- 4.030" x 3.48"
·Intake manifold- Dual-plane aluminum
·Oil pan, timing cover, valve covers included
·Engine fasteners: High tensile strength
·Warranty- 12 month/12,000 mi
Melting Slicks
Joined: Jan 2004
Posts: 2,672
Likes: 1
From: New Cumberland PA
Originally Posted by ajrothm
I would guess that the ZZ4 is better in the low to midrange but the LT1 would rip it up top.
on that statement.Horsepower is horsepower. With the two engine being very similiar on the horsepower figure, it has no bearing on whether its at 5200rpm or 6500rpm. The LT1 has a couple of extra ponies but to say it would rip it up top is a stretch of imagination.
