Originally Posted by NoahT
I have a77trans am, basic 6.6 400. The olds 403 came as a stock option too. I read an article that you could really beef up the 403...350 hp for around 1500 bucks. But what could i do with the 400 for $1500? I wanna keep it somewhat original, but with some muscle. which motor should i stick with? I hear the 400 is kind of easy to tear up when built. But then the 403 only has around 185hp/325lbs torque with 7:1 comp from factory....kinda weak. someone help me with my decision please.
you can bump up the compression on the 403 by putting 68-70 olds 350 heads on it. i had an '80 formula w/ a 403, 69 350 heads, and an edelbrock performer cam that would simply incinerate the tires w/ an open rear (and i mean both
tires, no brake torquing) that was w/ a stock aluminum 307 intake and stock exhaust, so if you do more, it oughtta fly. the 400 poncho is stronger to begin w/, though...