Originally Posted by 77pontolds
Wow! You folks were right. The 400 Pontiac makes my Firebird haul 555. It makes me want to put casters on the rear. It is quite a difference from the Olds 403. Now I have to be careful when I nail it, cause when it shifts into second gear, it wants to go sideways. Fun!!!
Glad to hear it. Do you have alum intake and hei? Your set to enjoy. They dont need much to be fun.
The 400 will not show a stock 403 trans much respect. If you havenet already best to have a great trans built next. That should be the next biggest drop in et for single improvment.
Not sure what purpose the 403 was built for but it was not performance or tq. it was not all that strong compared to the beating a new 400 will take. So not even sure why they built then. The 350 from olds and chevy and pontiac was comparable and had advantages. I just dont see the advantage to the 403. Most of gm products have a perfect nitch where they belong and were properly designed to work great at doing.