yes i totally agree with duneaholic. my case never broke (knock on wood) but my studs that connect the case to the cylinder broke. a girdle kit is a good investment

 

illing the head for performance carbs is usually called "decking" what they do is remove metal from the under side of the head to bring the cylinder had closer to the picton at top dead center(piston as high as it can go it the cylinder) it raises cylinder pressure and puts more force on the piston for the power stoke(when the piston travels down the cylinder)

its an extremly cost effective mod usually each point increase will net a 5 % gain. I can't remeber but beleive the 400 has a compression of 9.5 to 1 so increasing compression to 12 to 1. would give a 12.5% power increase. so with a torque pipe adding 5hp to a 37hp engine you would have 42hp x12.5%= 5.25hp increase.

keep in mind this is bench racing, and normally you can;t get an even power 5% increase across the board(motor to motor). this is based on a rule of thumb. it only cost me 35.00 to get my head decked and it was a strong gain. If I asume I got 8-9% horsepower increase its still a cost effective mod.


good luck. I wasn;t aware you could port for a low end pipe.,

 

ohh, and this is a fun calculator if you know the figures to plug in.

http://www.smokemup.com/auto_math/compression_ratio.php

 

i gues i wasnt aware either that it mattered on the exhuast...although i did knwo that if i wanted to go race porting...that i would want a race mod, so thats why im only getting trail porting.