what do you mean by maybe having to trim the 3800 spring to the right size? i am building a drag truck, i already have the valve springs.
Thanks

 

X2

 

The 3800rpm spring is approximately 1/4" longer than the stock/OEM spring. As such, one has two choices in correcting this:

- Install the longer spring as is and then advance the throttle-shaft indexing so as to take up the slack. IMO, this may present with issues of the throttle-shaft lever not being positioned right so as to have the governor spring pull as hard as it otherwise could.
- Trim the longer spring to match the stock/OEM spring length and put it all back together as originally found.

Hope this helps.

 

I pulled a 388 spring out of mine and no mistake it states 388 on my spring. What RPM range was this? I put in a 366.