I already took off all the emissions junk and swapped a 302 throttle body and ported the intake + larger injectors and fpr, it runs amazing....spins 35 inch cooper stt's pretty well. I want to swap a mild cam and if i can chevy rockers on the 240 head that is port matched. Is it possible? <!-- / message --> <!-- BEGIN TEMPLATE: ad_showthread_firstpost_sig --> <!-- END TEMPLATE: ad_showthread_firstpost_sig --> <!-- controls -->

Carbed block and EFI block are the same except for the <nobr style="color: darkgreen; font-weight: normal; font-size: 100%;" id="itxt_nobr_1_0">fuel</nobr> pump arrangement. 240 head to a 300 gives about a .5 bump in compression depending on whether or how much the block and/or head have been milled.

I thought you might like to see this.

 

either will work.....computer compatible just means does it produce X amount of manifold vacuum and will the ecm~fuel tables be able to keep the air/fuel correct.


If you do more towing or driving under 55mph, go with the supercam, if your truck is used more for highway driving, then the crane will do the trick but theres not alotta difference either way.


My two cents, dont go to the trouble of adding a v8 throttle body or mess with the emissions system.......you wont get any appreciable gain in power or mpg by doing so.


You can run higher ratio rockers on the efi head but you kinda have to look at it like this, if there was power to be had by adding .XX more lift to the cam lobe, then the cam company would have added it. With the efi head requiring pedastel mount rockers, its more trouble than its worth if you do. If you do opt for an aftermarket camshaft, you might wanna be sure to use that camshafts recommended springs or should cam failure occur, the cam company may not back replacement of the camshaft.


As a piece of mind, consider the earlier course metal timing gear set, sure the efi phenolic were put in many trucks but have from time to time been known to fail, its not neccessity but adds some confidence in the build.

Have you considered doing basic port/polish work on the head? If you have the tools readily available, that might be a better place to put your time and energy, vs spending cash on a camshaft.

 

"You can run higher ratio rockers on the efi head but you kinda have to look at it like this, if there was power to be had by adding .XX more lift to the cam lobe, then the cam company would have added it."

There are plenty of cams out there with that amount of lift. But, installing higher ratio rockers is reliable way to get more lift from a cam, without the undesireable affects of added duration.

Having said that, I would go with a mild cam, if I were you, and leave it at that. That way you won't have to get into expensive head work, like swapping out the studs for 'screw-ins'.

 

The crane or isky mentioned, have reasonable lift and spring pressure requirements, no need for studs.

Higher ratio rockers were originally intended as a tuning device...just adding higher ratio rockers to any given cam, will not guarantee power...and in my opinion, is a waste of time if your buying an aftermarket camshaft that has some amount of R&D put into it...unless you know the engine combination can benefit from it, as lets be realistic, even if there were to be gains to be had, we are talking single digit figures here, at best, unless extensive modifications were made.

There are kits out there that can be used to convert the pedastel to stud mount, and if using the cheap rockers mentioned earlier, but throw in the need for pushrods and known results...1.7's on a stock camshaft, which on the efi have been in the 5+/- hp to the wheels, using headers and ADFPR, so the question arises, is it worth the extra 150+/- if your adding a camshaft with higher lift anyway. With the thinking, without actual data, adding the higher ratio rockers to an aftermarket cam, might just be a prime example of throwing money at diminished returns.

 

There was one thing I wanted to mention: You wrote that if the cam co's thought they could get more performance by adding lift.... If we read about the chevy 250 inline, Isky makes the same 256 cam for that engine, but because of the rocker ratio, they get .492" lift. The engines are similiar, so why would the 250 benefit from such lift and not the 300?

The answer is that to get that much lift they would have to increase the duration too for the 300, and then it becomes undesirable for most people...unless you change the rocker ratio. Also, Isky's costs are reduced by marketing one cut. It has nothing to do with performance.

 

I got the new oil pump, rings, and frost plugs today.
As for pistons and rods, they are getting reused. Actually, I put the new rod bearings in today.
I still have to hone the cylinders and polish the crank.

I sold my '94 chevy (and kinda brought home 2 more Fords) but I think I can swing buying a cam since I found this and it's somewhat close to the COMP
Ford 240 300 RV Torque Camshaft Cam F150 kit lifters : eBay Motors (item 190327910231 end time Apr-08-10 10:47:30 PDT)

Just got a Victor Reinz gasket set off eBay for $45, parts store wanted $110 for the same set.
Still need head bolts, o'reillys said they can't get them even though the website shows them.

Before I took it back to school

 

That is a lot of duration in that cam. Are you sure it is computer compatible?

 

I suppose you could argue displacement but even then, both heads flow differently...and the intended purpose for the chevy 250 engine has a broader application, cars and trucks, not as narrow as say the 300 only used in trucks.

This is what we know, adding higher ratio rockers to a stock camshaft will net increase in power.

Logic would dictate, if you add an aftermarket camshaft as discussed, the isky or crane, you would get the additional lift, as well as duration and expect an increase in power..........the unknown, is whether adding higher ratio rockers would benefit the power further. If you know something I do not, then Id have to say for me personally, I might shy away from shelling out the bucks for additional lift......throw money at potential diminished returns.

Added duration isnt a bad thing...only reason someone would hang on a 256 duration cam and be afraid of more duration, is if they were convinced somehow anything more would net a mpg penalty or compromise low end tq and thats just not necessarily true.

There are many other companies besides comp and crane or isky for that matter that make camshafts for the ford 300.....clifford was big on "small" cams with big lift...maybe they were onto something.

Either way, higher ratio rockers are intended as a tuning device.....if you throw the cost of higher ratio rockers on top of a isky cam for example, you might as well have had a custom grind made.

 

Id rethink that cam.

This is whats gonna happen, you will see a low end tq improvement but your usable rpm will still be right around what you were getting with the stock cam...and you may have issues with your ecm, as Im not familliar with that cam or its affects on manifold vacuum. With that said, something simillar, the PAW grind, does work, is alot cheaper too.

With that said, Id look again real hard at the crane 260/272 you originally considered. What has happend with that cam so far, even in efi engines, is youll get more off idle tq and also get another 500 rpms to play with, which might not sound like much but will make for a nicer driving experience and should you decide to go from point A to point B fast as you can, youll be happier.

Just my two cents.

Build is coming along nicely, looks good.

 

The engine in the truck is almost ready to pull out. I'm going to check out the cam and lifters out of it and see if they are any better than my other ones. If so I will throw those in, for now anyway.

 

Make sure you keep the lifters in order. If you mix them up, throw them out. An old egg carton works great. Write the #'s on it with a felt pen.

 

I kept them in order, I might just use this cam to get me by for a while until I have more time and money. This truck shouldn't see a whole lot of miles once I get my diesel back on the road.

 

I will post some pics next week. I was going to take the camera today, but forgot (just got back from ag class chicago trip yesterday) We have 8 more days of school. I got the old engine out of the truck sunday. The other one is almost ready to drop in. I will probly haul the truck to school tuesday to start dropping the engine in. Hopefully it runs by friday.

Still have to prime oil pump and install dizzy, put new motor mounts in truck (they fell apart)

 

we will stay tuned

 

i run that cam in my EFI with no issues. real nice grind, good off-idle torque all the way to 3500-4000 rpm. i also opted for the steel timing gears, i just told the parts counter i wanted a set from a 79 F-150 with a 300.

i would listen to what motorhead has said, it saves me a lot of typing. he's be around here as long as i have, and we are close to the same thought level. BTW, nice to see ya around again motorhead!