This is topic 1.7 vs 1.6 for a tfs1 cam in forum Tech Talk at Northern California Ford Owners  .


To visit this topic, use this URL:
https://californiafords.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=6;t=022717
Posted by jaejae (Member # 7958) on :
 
already have the 1.6's would i benefit from 1.7's?
 
Posted by 68stanger (Member # 7842) on :
 
will it clear your pistons? are they notched or aftermarket?
 
Posted by jaejae (Member # 7958) on :
 
not sure asking you guys [Wink] ..stock pistons
 
Posted by wilit (Member # 3367) on :
 
You have to check to see if they clear. No one here ('cept for maybe Duncan Motors) knows how your motor is built.
 
Posted by JohnB (Member # 969) on :
 
Stock shortblock, GT40 heads, .043 head gasket, and that cam with 1.7's will leave you with .125-.130 clearance exhaust side...enough to live, as long as your springs are up to the task. Doublecheck to make sure your valve guides/guide seals aren't bottoming out on the spring retainers. This is a common problem with GT40's and any cam lift over .540.
 
Posted by jaejae (Member # 7958) on :
 
quote:
Originally posted by JohnB:
Stock shortblock, GT40 heads, .043 head gasket, and that cam with 1.7's will leave you with .125-.130 clearance exhaust side...enough to live, as long as your springs are up to the task. Doublecheck to make sure your valve guides/guide seals aren't bottoming out on the spring retainers. This is a common problem with GT40's and any cam lift over .540.
thats what i was really worried about john..duncan has mentioned that to me before..the valve springs are good up to .542
 
Posted by nitrous_bob (Member # 77) on :
 
tfs told me i'd hit with my 1.9/1.6 eddy heads using a 1.7 rocker for sure, and that i should clay them even with 1.6 rockers on that cam. thats the 200001 or whatever right ?

i'd call them and ask.
 
Posted by copcar (Member # 10113) on :
 
The 1.7/Stage 1 cam is a known combination but no matter what check your clearances. Also, your heads do not flow any better at the lift the Stage 1 is providing with 1.6's versus 1.7's. Typically, even with a spot on port and valve job the GT40's cap out around 520 lift. I just don't think you will get your hp/dollar worth by installing them. Typically that combo is seen on FAC 170's, AFR 185's and 165's. The GT40 valve springs will handle the lift just fine, however due to the ramp rate of that cam I would keep the revs under 6500. It is very easy to float a valve with that cam and those springs if you are not careful.
 
Posted by jaejae (Member # 7958) on :
 
quote:
Originally posted by copcar:
The 1.7/Stage 1 cam is a known combination but no matter what check your clearances. Also, your heads do not flow any better at the lift the Stage 1 is providing with 1.6's versus 1.7's. Typically, even with a spot on port and valve job the GT40's cap out around 520 lift. I just don't think you will get your hp/dollar worth by installing them. Typically that combo is seen on FAC 170's, AFR 185's and 165's. The GT40 valve springs will handle the lift just fine, however due to the ramp rate of that cam I would keep the revs under 6500. It is very easy to float a valve with that cam and those springs if you are not careful.
the heads have been ported pretty much to the max,they have upgraded trickflow valve springs,hardend valve seats,3 angle valve job..
 
Posted by Stan G (Member # 6226) on :
 
I doubt you will see 5 additional hp.
 




Fueled by Ford Mustang Owners
on CaliforniaFords.com