Yet another rocker arm question...
 

Hey everyone!
Im looking at all the rocker arm options for the 300, but i can't seem to find any rocker options for us guys with the fuel injected head. Is there a hidden secret I'm missing out on? I know they are ped mounted like the 351w. Admitting, i haven't done parts x- ref yet, but does anyone know of any rockers that fit?

There is a company making 1.7:1 ratio rocker arms that are bolt-in now. The brand name is Scorpion.

https://www.summitracing.com/parts/s...SABEgKKxPD_BwE

Those are some really nice pieces... almost too nice. Man they are pricy. I paid less than that for the truck...

I rarely have to pay more than $50 for complete engine cores. But that doesn't mean I'm not expecting to invest thousands to end up with a usable engine.
Let the games begin.

😈 you know it. I'm new to the ford scene, but I've been a diesel mechanic for eleven years. You have no idea the plans I have for my 96. Muhahahaha! I'm secretly planning to beef everything up first, then make stupid power: Three core radiator, dual batteries, 3g alt, electric fans, roller rockers, larger/better injectors, and an hx35g from a garbage truck . All stuffed in 2wd Eddie b f150 sb 5spd. I scored the truck for 200 bucks because the power steering pump locked up and the truck wouldn't crank. Already got the turbo too...

Get that turbo on it!!!!!!!! I have a gt35 on mine with a ported head and some other goodies. My heavy ass truck will wear out almost anything running the streets

that is awesome! Do you got any footage of your truck? I'd love to see it. On a side note, i posted a question on the <96 obs side, I'd like to hear your input, considering you obviously have some great knowledge behind you.

The Scorpion 1059 roller rockers saves you a lot of work and money if you need a full roller rocker.
You get the rockers, pedestal mounts and bolts.

https://cimg7.ibsrv.net/gimg/www.for...f22d0e47e8.jpg


Before these were available the only other option was to drill and tap the pedestal bosses in the head for studs.
Then you needed pushrod guide plates to keep the rockers aligned.
Then you still spend over $300 for roller rockers on top of all this.
Here is the last set I did using BBC roller rockers.
https://cimg6.ibsrv.net/gimg/www.for...1a2df589c1.jpg

How much power are you looking at making?

As far as numbers go, i have no idea. My main plan right now is to free up power, reduce friction, mass, and restriction, make things easier to maintain, and overall beef up common use items while maintaining reliability. Once that is accomplished, I'll see where I'm at with power.

Are you considering port work and bigger valves for the head?

I was actually thinking of replacing the head with a non air pump head. Maybe a good three angle valve job, port matching, and lighter valves. Other than that, i wasn't planning on any crazy porting or other work. It makes sense replacing it because a reman is less than 300 bucks.

I don't have any footage from racing but I would be happy to answer any questions you might have

The EFI head has shrouded intake valves in order to create swirl and good intake port flow doesn't occur until the intake valve lifts above .350". We are presently flow bench testing EFI heads and that is what we are seeing.
As a result you will struggle with having to use high boost levels to get reasonable power.

The chambers can be modified to increase low lift flow if you are good with a die grinder. Modified chamber on the right.

https://cimg3.ibsrv.net/gimg/www.for...1a6a04fa3d.jpg

The EFI head also has shorter valves (4.75") than the carburetor heads (4.81") which limits the valve lifts to less than .500"
This is important when you use higher ratio roller rockers with an aftermarket cam.
You have the choice of using the earlier 300 valve or the SBC 4.91" valves.

I've read about using a 240 head to help with compression ratio. How does modifying the chambers above affect compression ratio?
This is just a question. I am new to all this modifying.
john

hThe 240 and EFI head have about the same chamber volume around 68 cc.
The 300 carburetor head (up to 1986) has a 76 cc chamber
If you have a low compression 300 engine with a 76 cc chamber head and want to raise the compression ratio about 1/2 a point without changing pistons, then you would swap for a 240 head.
If you are racing, the 76 cc head will give you a 10.8 compression ratio using a flat top, .030" overbore piston while the 68 cc head yields an 11.8 compression ratio.

In the above case (post #13) the modified EFI head chamber should be around 75 cc.
Since the engine is going to be turbocharged, the compression ratio needs to be low so increasing the head chamber volume will mean the piston dish volume will be less.

Example: Lets say the compression ratio needs to be 8.5
Using a 4.030" cylinder bore and a 3 inch diameter piston dish with the piston at zero block deck clearance.
With the original 68 cc volume EFI head chamber the piston would need a 34 cc dish which is .290" deep.
The modified 75 cc chamber would need a piston with a 27 cc dish which is .230" deep