Why do the HP&TQ vary in 3400's & 3800's

[Mike J.]

I have a 3400 LA1 in my Rendezvous Rated at 185 HP and 210 TQ. The same engine in a Monte Carlo is 180 hp and 205 tq and in the Grand Am either 175hp w/RA or 170hp without. Also my 98 Regal had 195 hp & 220 TQ

when the same year GP had 200 hp and Lesabre's and Bonnevilles had 205 hp and 230 tq. In 99 the Regals got a better Air Filter Box and the HP went up to 200. I am mostly interested in the 3400 LA1 since it has such a high variance in the HP from car to car (170-185hp). Does any one know the true or likely reasons.

[Brian P]

more than likely from exhaust manifold and exhaust system differences....and I bet the 3400 in the N body has the small throttle body too

[Zonsolo]

What he said , but GM is also famous for just picking a number and going with it for marketing reasons.

 

Another thing they like to do is manipulate the heads/cam to be either more agressive to fit the profile of certain cars (pontiac), versus smooth power cuisers (buick/olds).

 

Ford does the same thing. The 4.6L in a mustang is rough idling and 260HP. Take the same engine, put it in a crown vic, and its suddenly so docile you can barely hear or feel it running and it only makes 190HP. Same bore/stroke, different compression ratio, heads, cam, intake. There is alot more to an engine other than its CID.

[STR]

GM will also play with the ECM between cars too

[GPRACER]

GM will also play with the ECM between cars too

 

Different PCM calibration makes a big difference. I reprogrammed my car with the code from a 99 N-body I don't know If I gained any hp but there's a definate improvement in feel and shifting in the tranny. Low end seems a little better too.