i need help with ideas for increasing HP on my 70' chevelle SS
lordoftheoctagon
06-29-2010, 05:43 AM
hi all, im new to this site and new to the world of cars haha. i really dont know much about them besides how to drive'em! i recently bought a 1970 chevelle SS. it has a 396 in it. i was hoping you guys could help me find ways to increase the horsepower on it? id like to keep the price range around 1K. so im open to all ideas? any help?
TONYABITZUSMC
07-29-2010, 12:13 PM
For 1k$ I would recommend a good exhaust system to include headers if you dont already have that done. Otherwise some other options might include an upgraded carburetor. I guess i would need to know a little on what the engine currently has done to it.
rebuild quadrajets
08-08-2010, 02:39 PM
hi all, im new to this site and new to the world of cars haha. i really dont know much about them besides how to drive'em! i recently bought a 1970 chevelle SS. it has a 396 in it. i was hoping you guys could help me find ways to increase the horsepower on it? id like to keep the price range around 1K. so im open to all ideas? any help?
does it have the factory carb i can modify it for you if you want
does it have the factory carb i can modify it for you if you want
dusty3
09-01-2010, 09:53 AM
If it truly is an ss model you should have a fine Holley carb on it already. I would definetely take a look at some headers, an H-pipe and some hi flow mufflers. Also a cheap and easy up grade would be an Edelbrock RPM Air Gap manifold, along with a K&N air cleaner. Check with Summit Racing or Jegs on pricing.
MrPbody
09-01-2010, 12:43 PM
350 HP and "smaller" 396s had Q-Jets in '70. Great carb, but the pre-74 models are "down" on CFM.
Agreed, good (not "cheap") headers will do wonders. We prefer Hooker for the old-school cars. Great fit and big power. Get "SuperComps".
Changing intake, carb and cam will also show big gains.
You should know, though, the '70 isn't REALLY a 396, it's a "402". Effectively a .030" over 396, it has a serious "drawback". A cast crankshaft instead of the good forging real 396s had. This should limit RPM to about 6,000, MAYBE 6,500. Beyond that, it's a roll of the dice every time. The 402 heads are also a bit of a slug. They're really 454 heads, so compression is lower. I HAVE seen a handful of 375 HP engines in '70s (probably had the 6223 forging for a crank), but 454 was the true "performance option". NOTE: The CAR was still called "SS396", even when equipped with 402.
FWIW
Jim
Agreed, good (not "cheap") headers will do wonders. We prefer Hooker for the old-school cars. Great fit and big power. Get "SuperComps".
Changing intake, carb and cam will also show big gains.
You should know, though, the '70 isn't REALLY a 396, it's a "402". Effectively a .030" over 396, it has a serious "drawback". A cast crankshaft instead of the good forging real 396s had. This should limit RPM to about 6,000, MAYBE 6,500. Beyond that, it's a roll of the dice every time. The 402 heads are also a bit of a slug. They're really 454 heads, so compression is lower. I HAVE seen a handful of 375 HP engines in '70s (probably had the 6223 forging for a crank), but 454 was the true "performance option". NOTE: The CAR was still called "SS396", even when equipped with 402.
FWIW
Jim
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