i have read in a few different threads here


https://mustangforums.com/m_2930286/tm.htm
https://mustangforums.com/m_2591461/tm.htm


that this cam from summit works very well with the stock 289 heads and doesnt need a new valve spring.

i talked to the tech line at summit and he said that there is no way that this cam will work with stock springs and after 4000 rpms i will be bending things.

my question is does it work or not. the heads were rebuilt with new springs a few thousands miles ago so they are still good. if i have to replace the springs then so be it but if i dont have to that would be great too.

 

who said it would work with stock springs?

If the tech from SUmmit says no way, then I'd be taking his advice.
Did you ask him what your options were for a very mild improvement on a stock rebuild?

 

both those threads i posted said stock springs worked with this cam

the tech guy said that cam was way too aggressive for a stock 289 which was completely the opposite of what both of the threads i posted said.

one of them has a computer model flowchart estimating a 68hp increase with the stock heads, headers and a 600cfm carb

 

pm 67mustang302 or Starfury...No offence to theother knowledgable engine guys but their names popped to mind 1st.

They should be able to help you but just emphasise the engine is still stock everything else.

Otherwise, enjoy what you got and start saving to build a replacement from scratch. THats what id do and i still say you'll end up happier.

good luck