351W rockers
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351W rockers
I was looking at possibly buying an intake for my 351 but i was reading that buying higher lift rockers would give me more gains than and intake would for half the price from what i was looking at. My question is what kind of rockers should i be looking for to go into my 94 F150 and at what lift will i have to change out my springs and other various valve train parts?
FTE Legend
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From: Ottawa, Ontario
1.7 rockers are a bolt on upgrade on these motors, no other parts needed, though some oil baffle clearancing may be necessary on the valve covers. Power gains are hard to put numbers on, but in general the more the valves open the more air the motor passes. You'll go from 0.422/0.448" lift to 0.448/0.476 lift, on 351 that should produce a noticable increase across the board.
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they have all these different types i was looking at on summit (roller tip,pedistal mounted,stud mounted, ect.) what do you have to run on these and whats the diff? also if you put 1.7 rockers in and you dont have to change the springs if you put a mor aggressive camin will you then have to change them out?
Cargo Master
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From: British Columbia
Rocker arms
The bolt on (pedestal mounted) roller rocker arms are simply that- the existing rocker arms are unbolted, then the new ones bolted on.
As Conanski said, "1.7 rockers are a bolt on upgrade on these motors, no other parts needed, though some oil baffle clearancing may be necessary on the valve covers." These are Summit part CRN-44746-16, Crane Energizer Pedestal Mount Roller Rocker Arms.
The stud mounted type require the heads to be removed and machined to accomodate them. Their studs are stronger than the pedestal mounted roller rocker arms' capscrews, but this is moot in most applications since these capscrews seem to be quite strong enough.
The roller tip type have a non-roller fulcrum, so are only half rollerized.
I believe you can use the slightly higher lift Mustang HO cam without changing valve springs. Maybe others can recommend other camshafts that will work.
So far as comparing the installation of bolt on pedestal roller rocker arms to swapping intake manifolds, the former is much simpler and cheaper.
As Conanski said, "1.7 rockers are a bolt on upgrade on these motors, no other parts needed, though some oil baffle clearancing may be necessary on the valve covers." These are Summit part CRN-44746-16, Crane Energizer Pedestal Mount Roller Rocker Arms.
The stud mounted type require the heads to be removed and machined to accomodate them. Their studs are stronger than the pedestal mounted roller rocker arms' capscrews, but this is moot in most applications since these capscrews seem to be quite strong enough.
The roller tip type have a non-roller fulcrum, so are only half rollerized.
I believe you can use the slightly higher lift Mustang HO cam without changing valve springs. Maybe others can recommend other camshafts that will work.
So far as comparing the installation of bolt on pedestal roller rocker arms to swapping intake manifolds, the former is much simpler and cheaper.
FTE Legend
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There is no need to upgrade the valve springs with 1.7 rocker arms, but almost certain you would need to with an aftermarket cam.. anything worth upgrading to at least. If you have plans to upgrade the cam soon then either do that instead of rockers or get 1.6 rockers now, the higher ratio rockers will put valve lift into dangerous territory with many aftermarket cams.
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whats the stock rocker lift? i saw in your sig conaski that you have a cam that you highly rec. i with thinking about that one seeing as its same motor but with the 1.7 rockers you will run into clerance problems? (valve to piston?)
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FTE Legend
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With the Crane 444232 you can use 1.7 rockers.. it's one of the few decent cams left with under 0.500" lift. But... you have a roller motor so this cam would require you change the lifters and pushrods as well which are added expenses and a backwords step. The Comp 35-351-8 would be a good candidate for your motor, matching springs would also be recommended.
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would a cam give me more of a gain than installing rockers? Ive heard here that when you install a cam you can move the power band up to higher rpm's i would like to keep my power band as low as possible right now.
FTE Legend
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From: Ottawa, Ontario
The 351 will can use some additional duration, it will broaden the powerband without impacting the low end. The F4TE cam in your 94 is well suited to the 5.0 but it strangles the 5.8. It's specs are 422/448 lift and 256/266 duration. The Crane has 448/464 lift and 268/276 duration, and comparing my truck to my fathers stock '95 there is no contest, my truck made more power everywhere. Adding rockers to the stock cam will be a benefit, but it won't be as much as upgrading the cam.
Postmaster
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Where in the RPM range a cam will develop its power depends on the specs to which it is ground. And there's a lot to cam design beyond duration and lift.
A new cam will give you 20-50 more hp all across the powerband. Different rockers might - MIGHT - give you 5 more hp.
Does your truck have headers and a free-flowing exhaust? If you don't you'd pick up more there than with new rockers.
A new cam will give you 20-50 more hp all across the powerband. Different rockers might - MIGHT - give you 5 more hp.
Does your truck have headers and a free-flowing exhaust? If you don't you'd pick up more there than with new rockers.
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I was looking at possibly buying an intake for my 351 but i was reading that buying higher lift rockers would give me more gains than and intake would for half the price from what i was looking at. My question is what kind of rockers should i be looking for to go into my 94 F150 and at what lift will i have to change out my springs and other various valve train parts?
FTE Legend
Joined: Jun 2006
Posts: 31,930
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From: Ottawa, Ontario
Thr rocker ratio multiplies the cam lift, so no you don't want 1.7 rockers with a 0.512 lift cam. Comp cams has a complete list of matching parts for thier cams in a PDF file on the web site. If you upgrade the springs on the heads you will also need upgraded pushrods, the stock pushrods are simply not up to the job.