460 Ford Forum banner
1 - 10 of 10 Posts

·
Registered
Joined
·
47 Posts
Discussion Starter · #1 ·
So here I am again thinking of ways to throw money at problems I don't have.

I've been driving my F100 as much I can that many here helped me put together a 521 for. This winter I upgraded the suspension, installed fuel injection and new wheels. Now that I got some MT's 30x12.5x15 under the bed and the CalTracs the truck is hooking up much, much better. So of course I need, ok I want more power. Currently I have the D3 heads from another user that were ported by Paul K and assembled with new stainless 2.25”/1.74” Ford Racing valves. Lem set me up with a stroker kit with custom pistons From RaceTech to get me to 10-10.5:1 compression. Because of the engine bay in the 1979 F100 there is almost NO room between the stock valve covers and the A/C box and brake booster. I know I could install a hydro-boost brake system but that still doesn't help with passenger side A/C box being in the way and I really would rather not cut it apart.

So my first question is what heads could I go with that would be an upgrade over what I already have, yet keep the "stock" profile with the set up I already have? And would the investment of said heads be worth it financially? As is $ per HP gained.

My other option is I am in the talks with someone with a 552 for sale with SCJ heads already on it. So I may just go that route, but again I'm not sure if the SCJ heads and rockers fit the stock head/valve cover profile? Can anyone confirm that the SCJ heads can use stock height valve covers? The engine is not near enough for me to drive to and measure myself and I'd hate to buy an engine, have it shipped to me only to find that doesn't fit.

Pic of the truck with the new front suspension and wheels for attention because words are boring. 😂
Wheel Tire Car Vehicle Truck
 

·
Registered
Joined
·
763 Posts
If you want to change to an aluminum head you only have a few options that will match the valve notches in youre current pistons. You probably have a flat top or slightly dished piston so youll need to use an "open chamber" head to keep the compression ration pump fuel tolerant. I believe trick flow power ports, edelbrocks or the Chinese speedmaster are youre only options. The A429's had the correct valve layout but i believe the chambers were much smaller.

The valvecover profile/location wont change or at least wont change much going from a D3 to any of the above options. Usually its the rockers that determine how tall the valve covers need to be.

Can you lower the engine in the chassis to gain a little heater box to valve cover breathing room?
 

·
Registered
Joined
·
47 Posts
Discussion Starter · #3 ·
Thanks wickettoby1. You seem to understand exactly what I'm asking. I haven't looked at changing the engine tower height because if memory serves me right there is clearance issues with the headers on the pass side. So going down isn't really an option. I feel that path would require reworking the exhaust and possibly trans mount. I want to say the pistons are -10 according to my notes I just checked on my phone. I need to go thru my paperwork and find it. I'll take a look at the power ports. I don't think I've looked at them yet. I do know that the d3ve's with 1.73 roller rockers do fit under the stock height valve covers. I'm not certain about the stud mounted rockers though. And yes, at $5+ a gallon I'd like to stay as close to pump friendly as possibly.
 

·
Registered
Joined
·
47 Posts
Discussion Starter · #4 ·
Looks like power ports are 78cc. According to the "virtual dyno" app on my phone. That would bring my compression to 11.81 and a minimum of 93 octane, which is what I've been running.
 

·
Registered
Joined
·
763 Posts
A static compression ratio of 11.8 is quite high but you’d have to run the dynamic comp #’s to see what that would be with you’re current cam. You may have the option of re-notching the pistons and using an AFR head which I believe are offered in 75 and 85cc chamber volumes.

I figured moving the engine location would/could add interference issues with the oil pan or headers or frame.
 

·
Registered
Joined
·
47 Posts
Discussion Starter · #6 ·
Any way I look at it I'm stuck. Major changes will be necessary to go any route it seems. The good thing, it's still running great and I can definitely drive and enjoy it as is. The current parts supply issues have me concerned though. So to me that's even more of a reason to buy or build a back up engine.

As for current mods I can do to fight my itch there's always nitrous. I think I should be able to safely shoot 100-150 with my current set up. I've never run it, might be fun lol
 

·
Registered
Joined
·
47 Posts
Discussion Starter · #8 ·
If I have the opportunity to have a back up on the shelf if something goes wrong I'm going to do it. The thought of the truck being down an entire year to get it fixed doesn't appeal to me at all. I drive it way too much and enjoy it.
 

·
Registered
Joined
·
66 Posts
One thing that will help is switching to a dual diaphragm brake booster from 70's f350. Increases brake power somewhat also. I cant remember specifics as its been some time but it wasnt a hard swap
 
1 - 10 of 10 Posts
Top