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Low Compression Street Engine's & Tuning Techniques Idea's...How Too's on low compression Engines.

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Old 02-10-12, 08:14AM   #16
Zedo
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Quote:
Originally Posted by SPDMETL View Post
Possible cheap-ass 455/200-4r combo for 2nd gen T/A.

School Me, Dudes!
10 HP per 1 point in compression

the engine will run better with premium and 9.25 CR on the street

don't build a Pontiac with less than 9:1 CR
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Old 02-10-12, 08:31AM   #17
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don't build a Pontiac with less than 9:1 CR
Every Pontiac I own is less than 9:1 and they run great. No cooling issues and they have fantastic torque. They run on 87 octane and NEVER ping. Idle great and no gas smell from the exhaust.


R.H.R.E, just dynoed a Poncho the other day. With no tuning (Ran out of time) he made almost 400 HP, I think like 375. With 8.7? SCR

IMHO, I would rather have almost 400 HP on 87 with no issues than 420 hp and some issues. That's just my .02$ Just keeping the conversation going....
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Old 03-05-12, 07:51AM   #18
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we built an 8:1 Pontiac 400, it was 030" with 7K3 heads and pistons with the 8 valve reliefs per piston, i.e. 16cc valve reliefs. It ran well and still runs well, but you can feel the loss of torque and HP with the heavy car. The 455 would pick up some of course, but if it was my car or engine build, I'd shoot for 9:1 or 9:25 CR and run premium as needed. These cars are not going to be driven much on the street anymore with the upcoming gas prices anyway. It's not like running 87 octane is going to save a szhitload of money. My Monte Carlo gets 22 mpg and I'm dropping $100/week on gas. If I drove a Pontiac 400 or 455 it would be $200 week/gas.

$900/month for gas with an old V8 w/carb with how much miles I drive

are you getting the picture here ? that's the cost of a mortgage on a 2000 sq. ft. house with property

it just ain't worth it anymore, when gas gets that high, it kinda takes the thrill and fun out of street musclecars
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Old 03-05-12, 12:27PM   #19
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we built an 8:1 Pontiac 400, it was 030" with 7K3 heads and pistons with the 8 valve reliefs per piston, i.e. 16cc valve reliefs.
Just about the same as my old 400 with the 6x-4 heads, that engine would run on the cheapest lowest octane gas, i'm sure it would run on beer and still make power.
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Old 03-05-12, 02:28PM   #20
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Just got the cam swapped out in my 8.3 scr 406 Poncho. Granted it is not a daily driver, but I put around 2 miles on it. (Started to snow) and it pulls really, really hard.

Went from 202/208 with a performer to a 220/226 with a Torker II. Idle is a tad choppy, but once I get the tune down....

I can run 85 octane and this car would still be fun to drive.


But I have to agree that gas is gas. 3.51$ right now.
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Old 03-05-12, 05:09PM   #21
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The 4X head is a good 8.5-1 head if you get the right casting marked one. Plus the hardened seats will also allow a 1.77 valve to be installed.



One of these days gonna put my custom hyd roller in it (In the 230's@.050 and 510 lift area.) that I put in Jim Butcher's 65 cat. and just see how fast it will run on 87 octane, plus idle around 750 in gear.
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Old 03-26-12, 11:10PM   #22
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I have the 4X heads on my '73 455 (.030) with the 1.77 ex valves installed. Some mild porting. GM 1 QJ intake (from a '71, with the crossover filled at the top to prevent an exhaust leak). 041 cam installed 4 degrees advanced. Nice idle with a little lope, pulls very strong up to 5200 rpms. Will break tires loose if you floor it under 30 mph on dry pavement. RA exhaust manifolds, 2.5 inch duals, 2004r (Jakes Performance) with a 3.42 gear, 27.5 inch tires, in a '66 Tempest Wagon.
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