I have a 1984 5.0 with a 89 5.0 302 carb'd. I have a set of gt40p heads I am going to put on. I want to put a cam in and change to roller rockers. Any suggestions on what type of cam/rocker/spring combo will work well with a carb'd motor? Will my performer intake manifold bolt right up with the new heads?
1984 mustang gt40p heads. What cam, roller rockers do I need?
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yes your manifold will bolt on
GT40p's use 5/16" pedestal mount rockers..i recommend Scorpion brand
for valve springs,use either CraneCams # 44308-1 or Trickflow # TFS-2500100
as far as cam choice,daily driver/street car id go with a trickflow stage 1, or for a more street/strip type of build i like the Comp XE270HR # 35-351-8
the valve spring kits i listed above will work well with either of those cams
dont forget to buy an adjustable pushrod length checker and measure for proper pushrod length,cuz you dont want to run weak stock pushrods with the added lift and higher spring pressures..you need new hardened pushrods
GT40p's use 5/16" pedestal mount rockers..i recommend Scorpion brand
for valve springs,use either CraneCams # 44308-1 or Trickflow # TFS-2500100
as far as cam choice,daily driver/street car id go with a trickflow stage 1, or for a more street/strip type of build i like the Comp XE270HR # 35-351-8
the valve spring kits i listed above will work well with either of those cams
dont forget to buy an adjustable pushrod length checker and measure for proper pushrod length,cuz you dont want to run weak stock pushrods with the added lift and higher spring pressures..you need new hardened pushrods
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thats up to you..lift really has nothing to do with piston to valve clearance,its in the duration,when the valve opening and closing events take place
the only thing that really limits lift is the valve springs..you want to stay within .060"-.080" from coil bind at peak valve lift..adding 1.7 rockers adds about .030" to your peak valve lift(it also technically adds about 2* duration as well)
comp actually makes two different xe270hr grinds,one for use with 1.6 rockers(the one i listed above),and one for use with 1.7 rockers(same basic specs,but ground on a tighter 112 LSA instead of the wider 114 LSA)..the 112 might be slightly more "radical", and the wider 114 LSA generally makes for a broader power range
TFS claims their spring kit is good for cams up to .542 lift,so that rules out using that kit with 1.7 rockers and the 112* xe270hr
i recommended those 2 spring kits cuz they require no machine work to the heads to install..
you could easily run the 112* xe270hr with 1.7 rockers if you buy different springs,probably need a double spring,which would be more costly and you'd need to have the seats cut on the heads by a machine shop,which isnt exactly free..but the Crane kit should be able to handle it too
personally,i like the Crane spring kit,its beefier,has more pressure on the seat, and handles a bit more lift..if you run the springs at the rec'd 1.950" installed height,they're actually good for .570" lift which would put you at .060" away from coil bind (crane advertises .550" max,which would be .080 from coil bind),
the only thing that really limits lift is the valve springs..you want to stay within .060"-.080" from coil bind at peak valve lift..adding 1.7 rockers adds about .030" to your peak valve lift(it also technically adds about 2* duration as well)
comp actually makes two different xe270hr grinds,one for use with 1.6 rockers(the one i listed above),and one for use with 1.7 rockers(same basic specs,but ground on a tighter 112 LSA instead of the wider 114 LSA)..the 112 might be slightly more "radical", and the wider 114 LSA generally makes for a broader power range
TFS claims their spring kit is good for cams up to .542 lift,so that rules out using that kit with 1.7 rockers and the 112* xe270hr
i recommended those 2 spring kits cuz they require no machine work to the heads to install..
you could easily run the 112* xe270hr with 1.7 rockers if you buy different springs,probably need a double spring,which would be more costly and you'd need to have the seats cut on the heads by a machine shop,which isnt exactly free..but the Crane kit should be able to handle it too
personally,i like the Crane spring kit,its beefier,has more pressure on the seat, and handles a bit more lift..if you run the springs at the rec'd 1.950" installed height,they're actually good for .570" lift which would put you at .060" away from coil bind (crane advertises .550" max,which would be .080 from coil bind),
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