Best all around OEM small block?
01-13-2003, 07:51 PM
#21
Safety Car
Re: Best all around OEM small block? (garagedweller2)
best SB all round = 327/350
best SB for the perf minded = 327/365
Comments:
IMHO the 327/300, should never have been put in a vette, 65-67 base should have been the 350HP engine. And I really didn't see the need for the 390HP 427 either, those people could have went with the 327/350.
The 70 LT-1 was a great engine, but under-cammed (sorry Duke
:) . I pulled the LT-1 cam and went with the 30-30, it felt better, but still a bit mild (with the 20 extra cubes.... ) (BTW I really liked the way the little Z-28 302 performed with that cam, it was pretty dead below 4000, but who cares.... it was excellent in the range the "package" was set up/intended to perform in). When I do any "Spirited Driving" the RPM's are 3500-4000 and above....... I really don't mind giving up a bit when just putt-putting around below 3500.
[Modified by 66427-450, 8:25 PM 1/13/2003]
best SB for the perf minded = 327/365
Comments:
IMHO the 327/300, should never have been put in a vette, 65-67 base should have been the 350HP engine. And I really didn't see the need for the 390HP 427 either, those people could have went with the 327/350.
The 70 LT-1 was a great engine, but under-cammed (sorry Duke
:) . I pulled the LT-1 cam and went with the 30-30, it felt better, but still a bit mild (with the 20 extra cubes.... ) (BTW I really liked the way the little Z-28 302 performed with that cam, it was pretty dead below 4000, but who cares.... it was excellent in the range the "package" was set up/intended to perform in). When I do any "Spirited Driving" the RPM's are 3500-4000 and above....... I really don't mind giving up a bit when just putt-putting around below 3500.
[Modified by 66427-450, 8:25 PM 1/13/2003]
01-13-2003, 08:48 PM
#22
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Re: Best all around OEM small block? (66427-450)
This is not brain surgery....L-79 a real package of power and driveability. :yesnod:
01-13-2003, 11:11 PM
#23
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Re: Best all around OEM small block? (Bluestripe67)
Power ... looks .. utility .. I vote for the L-79 too; though having the FI engine just trumps anything else on cool points alone, "finicky" notwithstanding .. :smash: . . I remember several times hearing of FI units that were for sale - - 100-150 bucks .. ! .. :eek: .. This was the mid 60's, mind you .. :lol: .. Shoulda-woulda-coulda wish I had mothballed one of them baby's .. ! ..
I'm leaning towards mechanical lifters now instead of the L-79 cam. Damn the lash adjustments, full speed ahead .. ! ... :D ..
mrg
01-14-2003, 04:58 AM
#24
Melting Slicks
Re: Best all around OEM small block? (SWCDuke)
#5 hands down. (not with your RR gears. ) 3.55 or above.
Had a 65 with 3.70's and close ratio. Best small block set up I know of.
But I bet you go with #1.
You seem to be leaning that way if you read your post.
Had a 65 with 3.70's and close ratio. Best small block set up I know of.
But I bet you go with #1.
You seem to be leaning that way if you read your post.
01-14-2003, 08:54 PM
#25
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Re: Best all around OEM small block? (Bluestripe67)
Like in the early 70's ( for me) solid lifter's was and still are finger candy I love mine and would not trade. :steering:
01-15-2003, 08:14 PM
#26
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Re: Best all around OEM small block? (propwash)
SWCDuke said "..the 327/365 wasn't as good on the street.." I have a question about that. My dad had a '64 327/365 that acording to him and others, was untouchable block to block, even against BB's. Granted, the engine had been totally balanced and the first time he went for 2nd gear, the clutch pedal wasn't there, having been sucked to the floor. (A heavy duty clutch solved that problem.) The 4.56's definetly helped in hooking up. My question is, does the gearing make that big of a difference between these engines? I had always assumed the 365 was the ultimate in sb's, even over the lt-1, due to less weight between the respective cars. What's the skinny?Classic
01-15-2003, 08:58 PM
#27
Melting Slicks
Re: Best all around OEM small block? (Classicvette63)
The 4.56 rear will overcome the 365's low end torque problem. With a more reasonable street rear end, like a 3.70 or 3.55, the 365 would probably suffer. The 327/350 would not.
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01-15-2003, 09:34 PM
#28
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Re: Best all around OEM small block? (62fuelie)
To amplify on the above the 30-30 cam sacrificed a lot of low end torque for a little more top end power. In my original post I asked for views on the best street engine for the average vintage Corvette enthusiast, which does not include street racing.
In developing the LT-1 cam, Chevrolet started with the 30-30 cam and made some significant changes to improve low end torque. Primarliy this consisted of using essentially the same exhaust lobe, but advanced it about eight degrees and shortening the inlet duration and advancing it about 4 degrees. This combination - much earlier exhaust opening, less overlap, and slightly earlier inlet closing produced about the same bottom end torque as the L-79 cam with only a slight loss of top end power available with the 30-30, and that's why I recommend the LT-1 cam for all solid lifter SB rebuilds.
It's the culmination of about 15 years of valve timing R and D for a high performance small block. It's the average power available through the rev range that determines acceleration performance, not peak power.
Duke
In developing the LT-1 cam, Chevrolet started with the 30-30 cam and made some significant changes to improve low end torque. Primarliy this consisted of using essentially the same exhaust lobe, but advanced it about eight degrees and shortening the inlet duration and advancing it about 4 degrees. This combination - much earlier exhaust opening, less overlap, and slightly earlier inlet closing produced about the same bottom end torque as the L-79 cam with only a slight loss of top end power available with the 30-30, and that's why I recommend the LT-1 cam for all solid lifter SB rebuilds.
It's the culmination of about 15 years of valve timing R and D for a high performance small block. It's the average power available through the rev range that determines acceleration performance, not peak power.
Duke
01-15-2003, 10:23 PM
#29
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Re: Best all around OEM small block? (SWCDuke)
It's the culmination of about 15 years of valve timing R and D for a high performance small block. It's the average power available through the rev range that determines acceleration performance, not peak power.
Duke
Duke
Average power through "the" rev range is the point. If you have 365/375 with a close ratio 4 speed, 4:11's, or 4:56's, and shift at ~ 6700, what do you think your RPMs will drop to when running thru the gears? I guess that would be the "range" of intrest for those focusing on maximum acceleration. As far as street driving, we all have different driving styles....... some guys, even when just crusing along, keep the revs up, others are up shifting much sooner. I think you know what I mean-- I know guys that wouldn't think of "flooring it" below 4000, others that want performance from 2000 to 5000, or so. We just need to get the high RPM combo's in the hands of the high RPM drivers, and the low RPM combo's in the hands of the low RPM drivers.... then at least everyone will be happy (although still probably think the other type needs to be shown the "error of their ways" .... that's just human nature... lol)
:seeya
[Modified by 66427-450, 10:27 PM 1/15/2003]
01-16-2003, 01:53 AM
#30
Re: Best all around OEM small block? (66427-450)
Like Duke pointed out, the best out of the box small block for the all around vetter.
I think an LT-1 cam with 3:70's would be an all around perfect engine.
My 327-365Hp car had 3:36's when I got it. Wow, that car really left some low end torque to be desired. Although the top end was great with the 3:36's. 120 mph and it just wanted more.
Back to the last post, what is your driving style. When cruising my engine stays around 2500 rpm, and with the 4:11's, 4500 RPM is just a 1st gear downshift away. The 4:11's cover up the dead gap in first gear. Once out of first gear (shift at 6500RPM) the tack falls to 4200 RPm, all ready to go again.
If you remember I took my vette to Thunder Valley this summer and my best time was 13.46 on big-o-tires off my dads buick. I was fairly conservative on my launches due tire spin. I basicly just let the clutch out like I was in traffic and just floored it. The second run I launched at 4K+ and had tire spin all through 2nd gear, time was in the 14's on that run.
Mark
I think an LT-1 cam with 3:70's would be an all around perfect engine.
My 327-365Hp car had 3:36's when I got it. Wow, that car really left some low end torque to be desired. Although the top end was great with the 3:36's. 120 mph and it just wanted more.
Back to the last post, what is your driving style. When cruising my engine stays around 2500 rpm, and with the 4:11's, 4500 RPM is just a 1st gear downshift away. The 4:11's cover up the dead gap in first gear. Once out of first gear (shift at 6500RPM) the tack falls to 4200 RPm, all ready to go again.
If you remember I took my vette to Thunder Valley this summer and my best time was 13.46 on big-o-tires off my dads buick. I was fairly conservative on my launches due tire spin. I basicly just let the clutch out like I was in traffic and just floored it. The second run I launched at 4K+ and had tire spin all through 2nd gear, time was in the 14's on that run.
Mark
01-16-2003, 10:57 AM
#31
Re: Best all around OEM small block? (ghostrider20)
It is interesting to look at the NHRA adjusted HP numbers. They use a system combining a HP/WT ratio with ET index. An engine can gain or lose HP based on record ET for that class.
Here are some numbers listed by year, cu in, factory HP, NHRA adjusted HP.
1963 327 340 275
327 360 285
1967 302 290 305
327 350 300
1970 350 350 370
350 370 400
2002 350 345 340
The 1970 engines look like best SBs according to this system. They are rated higher then some BBs. LT1 for performance, 350/350 as driver. I had a 1970 Corvette 350/350, M20, 3:36 gear. This was a great combo as overall driver. It would get 20MPG highway if driven for economy and would beat a 396 350 hp Chevelle at drags.
Here are some numbers listed by year, cu in, factory HP, NHRA adjusted HP.
1963 327 340 275
327 360 285
1967 302 290 305
327 350 300
1970 350 350 370
350 370 400
2002 350 345 340
The 1970 engines look like best SBs according to this system. They are rated higher then some BBs. LT1 for performance, 350/350 as driver. I had a 1970 Corvette 350/350, M20, 3:36 gear. This was a great combo as overall driver. It would get 20MPG highway if driven for economy and would beat a 396 350 hp Chevelle at drags.
01-16-2003, 01:08 PM
#32
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Re: Best all around OEM small block? (66427-450)
Yes the gear spacing has a lot to do with the usable rev range, but this only applies to maximum acceleration performance.
The revs will drop by the shift point, divided by the "intergear ratio".
Muncie CR gearing is 2.20, 1.64, 1.28, 1.00
Intergear ratios are: 1-2, 2.20/1.64 = 1.34
2/3: 1.64/1.28 = 1.28
3/4: 1.28/1.00 = 1.28
Shifting at 6700 the revs drop to:
1-2: 6700/1.34 = 5000
2-3 and 3-4: 6700/1.28 = 5234
As you can see the CR trans keeps the engine in the power "sweet spot" between the torque peak and redline, which will maximize the average power under the curve.
Of course, this doesn't apply to street driving where low end torque for normal driving is relatively more important, but the 365 combined with the CR trans and a short gear will make it a very fast race car, but on the highway it will feel like a five-speed with no fifth gear. Conversely if you have a tall final drive it will feel like a five-speed with no first gear.
Duke
The revs will drop by the shift point, divided by the "intergear ratio".
Muncie CR gearing is 2.20, 1.64, 1.28, 1.00
Intergear ratios are: 1-2, 2.20/1.64 = 1.34
2/3: 1.64/1.28 = 1.28
3/4: 1.28/1.00 = 1.28
Shifting at 6700 the revs drop to:
1-2: 6700/1.34 = 5000
2-3 and 3-4: 6700/1.28 = 5234
As you can see the CR trans keeps the engine in the power "sweet spot" between the torque peak and redline, which will maximize the average power under the curve.
Of course, this doesn't apply to street driving where low end torque for normal driving is relatively more important, but the 365 combined with the CR trans and a short gear will make it a very fast race car, but on the highway it will feel like a five-speed with no fifth gear. Conversely if you have a tall final drive it will feel like a five-speed with no first gear.
Duke
01-16-2003, 05:24 PM
#33
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Re: Best all around OEM small block? (66427-450)
It's the culmination of about 15 years of valve timing R and D for a high performance small block. It's the average power available through the rev range that determines acceleration performance, not peak power.
Duke
Yes, that certainly makes sense.....
Average power through "the" rev range is the point. If you have 365/375 with a close ratio 4 speed, 4:11's, or 4:56's, and shift at ~ 6700, what do you think your RPMs will drop to when running thru the gears? I guess that would be the "range" of intrest for those focusing on maximum acceleration. As far as street driving, we all have different driving styles....... some guys, even when just crusing along, keep the revs up, others are up shifting much sooner. I think you know what I mean-- I know guys that wouldn't think of "flooring it" below 4000, others that want performance from 2000 to 5000, or so. We just need to get the high RPM combo's in the hands of the high RPM drivers, and the low RPM combo's in the hands of the low RPM drivers.... then at least everyone will be happy (although still probably think the other type needs to be shown the "error of their ways" .... that's just human nature... lol)
:seeya
[Modified by 66427-450, 10:27 PM 1/15/2003]
Duke
Yes, that certainly makes sense.....
Average power through "the" rev range is the point. If you have 365/375 with a close ratio 4 speed, 4:11's, or 4:56's, and shift at ~ 6700, what do you think your RPMs will drop to when running thru the gears? I guess that would be the "range" of intrest for those focusing on maximum acceleration. As far as street driving, we all have different driving styles....... some guys, even when just crusing along, keep the revs up, others are up shifting much sooner. I think you know what I mean-- I know guys that wouldn't think of "flooring it" below 4000, others that want performance from 2000 to 5000, or so. We just need to get the high RPM combo's in the hands of the high RPM drivers, and the low RPM combo's in the hands of the low RPM drivers.... then at least everyone will be happy (although still probably think the other type needs to be shown the "error of their ways" .... that's just human nature... lol)
:seeya
[Modified by 66427-450, 10:27 PM 1/15/2003]
01-16-2003, 06:07 PM
#34
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Re: Best all around OEM small block? (SWCDuke)
Shifting at 6700 the revs drop to:
1-2: 6700/1.34 = 5000
2-3 and 3-4: 6700/1.28 = 5234
As you can see the CR trans keeps the engine in the power "sweet spot" between the torque peak and redline, which will maximize the average power under the curve.
Duke
Funny.... those boys at GM that worked up the option "packages", and limited certain deviations, knew what they were talking about ! I've long argued, "stick to the GM "combos" ! "....... they were VERY well thought out (i.e., head size, cast/forged pistons, cams, 2/4 bolt mains, cast/forged cranks, compression, gearing, etc. etc.) How many times has some Dude put a L-88 size cam in a 390HP 427, ported the heads, added headers and gears, then took the engine to the cams RPM's range just to have catastrophic bottom end problems ?
My 66 is getting set up for 4000-7000 (to "make big power" there and "stay together" up there), then it's just a matter simply changing the gearing/tires to suit the "high performance" use.
Again, thanks for numbers - Mike :seeya
01-18-2003, 02:56 AM
#35
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Re: Best all around OEM small block? (SWCDuke)
Hey, I thought you were a cop, Mac. So what are you doing playin' lawyer? ;)
Duke
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01-18-2003, 12:26 PM
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Re: Best all around OEM small block? (SWCDuke)
The absolute best small block is the 1970 LT1 at 370 HP. Just add Rochester Injection and it`s complete. Solid lifter cam, and 11.25 compression, and 202 heads says it all. :thumbs: :thumbs: :thumbs: :lol:
