New to this site and found it while I was trying to figure out a engine suffix code. I have a 1968 Impala that I trying to confirm the engine HP. I believe it is a 275HP. The problem I'm having is the suffix code is stamped HH, yet in Alan Colvin's book this is not listed in my copy. Searching on the internet I have found that suffix to be for a 327 250hp '68. So here's the confusing part, everthing else seems to be correct for a 275hp, the heads, distributor and even the original bill of sale that I have from when the car was first purchased. Here's what I have:
Vin and serial stamp on block jive so I'm quite certain it's the original
Useage stamp is: V0417HH
Block: 3914678 D168
Intake: 3919803 C218
Heads: 3917291 D18 Double Humps
Dist: 1111297 8D10
Options: TH400, PS, Pwr Disc Brakes
If anyone has any insight or info that could help with the suffix code, It would be very much appreciated.
Thanks alot. Steve.
CodeYearCIDVehicleHPRPOTransCarbCommentsHH65327Corvette365L-764-spd4-BrlHolley, Hp Solid CamHH66327Corvette300BaseManual4-BrlHolley, Hyd Cam, A.I.R.HH67327Corvette300Base4-spd4-BrlHolley, Hyd Cam, A.I.R.HH68327Impala250L-73Power glide4-BrlHyd CamHH69350Impala300L-48T-H 4004-BrlHyd Cam
Hi Jake, thanks for replying.
I couldn't get that link to work either.
HH 68 327 Impala 250 L-73 Power glide 4-Brl Hyd Cam
The info above that you posted is what I was coming up with also on the internet.
What confuses me is mine seems to be a 275hp going by the heads, etc. and that the engine has never been touch and the TH400 trany is also original since the stamp on it matches VIN.
I'm kind of puzzled???
Horse power ratings are all a lot of smoke and mirrors anyway. The factory was still measuring gross horse power back in this time frame. In the gross HP rating there were no accessories attached to the motor (not even a water pump) and it was running through the stock exhaust system. The longer single tail pipe in your application could be responsible for the drop in 25 Gross HP numbers.
If it makes you feel any better it only takes about 7 horse power to push your Impala along at 40 mph on a level hard dry surface (over come frictional losses). It takes a great deal more power to accelerate it to that speed, but it is not horse power that motivates a car; it is torque! Horse power is only of interest to those that want to run high bank oval track cars as they need horse power to overcome aerodynamic drag and friction. If you want to accelerate for one speed to a faster one you need torque. The faster you are traveling the more torque you need to accelerate (it increases as the square of the velocity aka speed).