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Here’s a pic out of my Haynes/Chilton book - so don’t flame the camera operator 😜
I have been lead to believe that the cam specs for my truck ‘94 F250 351W (Roller Block) was something abysmal like
.422 intake and .448 exhaust. But to my amazement (from the book info) the cam lift is .278 Intake / .283 Exhaust - so the valve lift actually more like .4448 (.445) intake & .4528 (.453) exhaust using the factory 1.6 rockers.
So with me using 1.72 Scorpion Racing Roller Rockers it will be more like - .478 Intake / .4867 (.487). Sure I could get a cam - blah, blah, blah - but I’m merely updating everybody’s info (or maybe this has been put out before and I missed it) 😳🤔😜
Here’s a pic out of my Haynes/Chilton book - so don’t flame the camera operator 😜
I have been lead to believe that the cam specs for my truck ‘94 F250 351W (Roller Block) was something abysmal like
.422 intake and .448 exhaust. But to my amazement (from the book info) the cam lift is .278 Intake / .283 Exhaust - it’s actually more like .4448 (.445) intake & .4528 (.453) exhaust using the factory 1.6 rockers.
So with me using 1.72 Scorpion Racing Roller Rockers it will be more like - .478 Intake / .4867 (.487). Sure I could get a cam - blah, blah, blah - but I’m merely updating everybody’s info (or maybe this has been put out before and I missed it) 😳🤔😜
i wouldnt exactly trust that manual for that info. which engine option is the roller? heres more specs heres more specs heres more specs heres more specs heres more specs heres more specs
And the cam specs are the same from the service manual to the Haynes/Chilton book, correct? Cam lift for ‘H series’ .278/.283? It was the other info that was previously mentioned that was off.
I do Love the Service manual info though. As you can tell, I do not have a Service manual, I had one when we owned our first ‘94 F250 351w ZF-5 2wd, but when we sold the truck, it went with the sale.
I don't think either one of those documents is 100% correct, all the info I have gathered over the years suggests the following..
The static CR of an EFI 5.8 is 8.8:1, 8.3:1 was the smog era motor('75-86) that used heads with larger combustion chambers.
The cam in the early flat tappet EFI motor and earlier 2V carbed version is a relatively mild single pattern cam... 0.416 lift and 260 deg duration seat to seat at the valve. I have never seen the 0.050" lift numbers published but I suspect it's fairly tight at arond 195-200deg.
The 351HO got a special RV cam borrowed from the marine division(allegedly) that produced 0.444/452 lift and 206/221 deg duration at 0.050" lift... likely 270/280 deg seat to seat.
The gen1 351 Lightning used a different cam with .0416/445" lift, 198/208 duration at 0.050" lift, 260/274 duration seat to seat.
AFAIK in '94 the motor got the same F4TE "explorer cam" used in the 5.0 roller motors, that cam produces 0.422/448 lift, 256/266 duration seat to seat at the valve.
All cam specs matter but lobe duration and cernterlines play a bigger role in determining how much and where power is produced.
My 88 sales book showed 8.8:1 for 351W and 9:1 for 302. Perhaps the earlier 302 were 8.3:1 with E6 heads?
Once I saw long ago the 302 flat tappet was somewhere around .380/.390 lift. 177/183 dur at 0.050 around a 111LSA. I figure Ford was just using up old stock as even my 05/88 had a roller block.
Any thoughts why the Lightning had a weenier camshaft like the 93 Cobra did also? Always odd to me.
My 88 sales book showed 8.8:1 for 351W and 9:1 for 302. Perhaps the earlier 302 were 8.3:1 with E6 heads?
E6 head had 64-65cc chambers IIRC but all the other smog era heads had 69cc chambers.
Originally Posted by Hit Man X
MyOnce I saw long ago the 302 flat tappet was somewhere around .380/.390 lift. 177/183 dur at 0.050 around a 111LSA. .
Yes it was tiny and the engine performance reflected that. I think I still have one of those cams here somewhere, I was going to measure it but never got around to it.
Originally Posted by Hit Man X
MyAny thoughts why the Lightning had a weenier camshaft like the 93 Cobra did also? Always odd to me.
Just using what they had on the shelf, this was an era when they didn't put any real money into truck performance. The limited run 351 CobraR mustang had the exact same engine as the Lightning but somehow it now made 300+ horsepower, I suspect somebody spent some money on a proper camshft for it.
Yep, my 185hp/270tq 302 was laughable in stock form plus undergeared with a 3.55:1 made it pretty lame to drive. Right about 4000 power just nosed off. I had my stock flat tappet to send to Cam Motion in LA to be measured, but it was destroyed by Hurricane Harvey sadly. :/ Oh well.
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