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Old 05-28-2020, 10:52 AM   #169
oldman


 
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The Olds head is like the 1968 up 440 Dodge head, it has an open combustion chamber:
https://www.cartechbooks.com/techtip...cylinderheads/

30 to 40 years ago Hughes made a piston specific to the 440 that would take away all the quench and squeeze the charge into a small area. These were odd shaped positive deck pistons and had to be clay-ed to each piston chamber. It allowed me to run 10.5 pistons on pump gas across the HUGE 440 piston. Any modern chamber is basically a heart shaped head and a positive deck piston so ally action happens in the heart at TDC (no quench). Looking at the Olds head you are stuck with large chamber (unless somebody makes a specific piston for it). Probably going to have to drop 1 point or 1.5 points to run 92 octane. 5% loss in power for each point (you got plenty). What is your CR right now? My 2nd build on my 440 I had 11:0 forged and that was good till the early 80s, that when I went with the Hughes piston which worked till I sold the car a few years ago. If I did not do a Hughes piston I would have done 10.0 or 9.5, that is just the reality of the chamber design and the large bore.
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Old 05-28-2020, 11:05 AM   #170
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I am in the range of 10.5 to 11 to 1 my heads were 64CC to start with but with limited forged pistons to choose in 99 had to take a dished piston, in order to bring compression back up the heads were decked and material was taken out to reduce CC and up CR, I have done a measurement on a stock set of heads I have and it was close to 1/8" taken so will need to keep a dished piston and go with a thicker gasket.
In Ontario Sunoco 94 is the highest octane that you can get so I will run it on that so thinking that 9.5 to 10 would be the CR to go with.
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Old 05-28-2020, 11:18 AM   #171
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roger that
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Old 05-28-2020, 09:05 PM   #172
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Quote:
Originally Posted by oldman View Post
The Olds head is like the 1968 up 440 Dodge head, it has an open combustion chamber:
https://www.cartechbooks.com/techtip...cylinderheads/

30 to 40 years ago Hughes made a piston specific to the 440 that would take away all the quench and squeeze the charge into a small area. These were odd shaped positive deck pistons and had to be clay-ed to each piston chamber. It allowed me to run 10.5 pistons on pump gas across the HUGE 440 piston. Any modern chamber is basically a heart shaped head and a positive deck piston so ally action happens in the heart at TDC (no quench). Looking at the Olds head you are stuck with large chamber (unless somebody makes a specific piston for it). Probably going to have to drop 1 point or 1.5 points to run 92 octane. 5% loss in power for each point (you got plenty). What is your CR right now? My 2nd build on my 440 I had 11:0 forged and that was good till the early 80s, that when I went with the Hughes piston which worked till I sold the car a few years ago. If I did not do a Hughes piston I would have done 10.0 or 9.5, that is just the reality of the chamber design and the large bore.
That is why for many years I had piles of 67 915 heads setting in my shop .. Then came the edelbrock heads and I said bye bye to my piles of 915s ..
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Old 05-28-2020, 10:47 PM   #173
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That is why for many years I had piles of 67 915 heads setting in my shop .. Then came the edelbrock heads and I said bye bye to my piles of 915s ..
yep they were gold heads back in the day.
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Old 07-14-2021, 04:32 PM   #174
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The latest Pure Stock Drags shows a move to thee engines that are surprisingly strong:
340 cid both 6 pack and thero-quad
Olds 350 W31 / ram rod now closing on 350 net HP....
350 LT1
the latter two hampered by poor exhaust manifolds but the 2.5 mandrel exhaust allowed (and two mufflers) is really letting these engines work
https://www.psmcdr.com/pastyears
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Old 07-18-2021, 12:36 AM   #175
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Originally Posted by oldman View Post
I had a Challenger before the, and a 4th gen Camaro before that. Anyway the topic of how bad action the 60 and 70 muscle cars always comes up. Here is the long used list:
https://www.streetmusclemag.com/news...t-muscle-cars/

I would like to address a few and need help on the 455 GS Stage 1.

first the Shelby Cobra, it is
a) not a muscle car
b) the special blue dot probably were race tires not issued when the customer purchased the car, they were bigger at 8.15 than the "production" Cobra also. Note that production was so low and any initial customer for these cars were actually driving and purchasing prototypes. The car tested was returned by Sammy Davis Jr as undrivable, it was sold to a rich guy in CA, at which point the car killed him.
c) outside of a mechanic on-site the car probably could not even work must less perform.
d) I'm actually OK with on the list as a tribute to American Graffiti and the two Japanese guys..

The next car I have an issue with is the 440 six pack 12.91. I have that issue of the test, bone stock off the truck (sure it was already prepped by Mopar techs). I was drag prep by the SuperStock staff, every tricked used, take out al weight, cool water in the radiator between runs, prep track, pro driver, pre non-stock distributor, fresh plugs, no air filer (base plate left on), loosen and remove belts, 66 PSI in the front tires. Mopar tech on site to tune the carbs. But essentially "stock". It just was NOT show room stock. Say .25 is the minimum that a prepped but drive off the lot car would do.

The next car and now I need some help is the Stage 1 455, even Buick guys question how stock this 455 was. It is .5 to 3/4 second faster than any other 455 road test ( Motor Trend 13.38@105.5) . It was a know factory marketing car. There was a 455 stage 1 site (think it was V8buick.com) that was highly critical of how "stock" this 455 was. Others have noted that the rear gear ratio was NOT available on the auto. This is probably my favorite Muscle Car, but it should be listed with a realistic time. It was tested by Hot Rod it was 14.4 @ 96 MPH. Lets here it from guys that “know”.

Oh and I forgot the Oldham (Muscle Car Confidential). Wrote a fake road test of the stage 1, but his seat of the pants said it was a low 14 second / very high 13s car. Seems about right, he drove many of them.

Last is my favorite engine, really hate that it is over-hyped. The list ends at 13.99 and there was never a 340 stock that did that time. I literally have EVERY road test from the time and the average is about 14.7 at 96 MPH. Ronni Sox in a long term build target at a pro stock build “claimed” his 1968 340 Dart with prep did a 13.99. Believable because it is Ronni Sox, and this is not a show room stock 340. The fastest of fast was a 1968 Dart 4 speed (biggest cam), lightest car. 6/69 Super Stock bone stock got 14.6 out of it, with full drag prep of stock stuff (see 440 list above), they got 14.21 and 100 MPH. One of the few 340 ever tested to break 100 MPH in the ¼ “stock”. The engine has been strapped to a dyno and with stock manifolds it makes about 260 engine HP. Rated up to 320 HP in super stock depending on carb, this is a blue printed engine with open headers, no alternator, no air cleaner… The small AVS car from memory was 305 HP? Super stock gets confusion as cheater cams can be used with stock duration but ramp profiles that would wear out in a week of street driving. Same goes for modern Stock Car Drags. The last buid-up article of a low 13 second 340, the owner said the cam can only go a few hundred miles…

OK lets hear it on the Buick…


found a link to actual 455 article, says no A/C so I would guess the 3.64 ratio is correct even with an auto.
http://www.buickhorsepower.com/?opti...d=34&Itemid=40



Having said all that...all the test cars were traction limited. Either the throttle was feathered coming off the line to control traction or they just stomped it and spin the tires through most of first gear. Look at some of Bud Lindenmen's tests from the 60s and 70s, they were smoking the tires in these e/t tests.

Last edited by Nilly Welson; 07-18-2021 at 12:41 AM. Reason: kkd
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Old 07-21-2021, 01:29 PM   #176
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I'm glad I started this post:
1) The Shelby Cobra should stay on the list but it went 13.2 on blue dots. That 12.2 was a quote for Shelby himself and was NOT in any form related to a Cobra customers could actually get. The article itself is a mess, actual testing of the car in the article was 13.2.
2) The 340 that are performing are the 6 pack and the thermoquad 1970, both excellent setups, but only for 1 year, before the CR drop. I will say that even with the CR drop the 340 was rated at 240 net with thermoquad and OK exhaust manifolds.
3) The Olds 350 and the LT1 1970 (every chevy SB) have poor exhaust manifolds the Olds is the worst (one side) as the other side is bigger because most 350 Olds engines came with single exhaust one side manifold feeding into the other side (which had bigger passages, by a little). Added that many FBody upto 1969 if not all came with only ONE muffler, a traverse one in the rear. The exception that I know of is the Z/28 chambered exhaust, I had one and it was HECK of loud. Don't think it flowed all that well either. Since the pure stock rules allow 2.5" mandrel exhaust cars like the ZL1 1969 Camaro are probably making 50 more HP just going from a single muffler to twin 2.5" free flow mufflers. Mopar IMO of course always had a nice twin muffler setup for the factory.
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Last edited by oldman; 07-21-2021 at 01:41 PM.
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