I have a stock 1979 F100 Lariat with a 351m. I just pulled off all of the smog equipment. (All of the smog equipment is for sale and if someone doesn't buy it soon, I'm scrapping it.) I have replaced the intake/carb with an Edelbrock 400 and a Holley 600. That is all I have done to it so far.

I have a 1986 Mustang 5.0 and my cousin installed 1.72 Roller Rockers in it and it was like lobing up the cam with the benefit of roller rockers. And it was certainly easier than installing a new cam. So I thought I might do the same here and add roller rockers to the truck. Summit has a set for a little over $100:

https://www.summitracing.com/parts/sum-141709pl

Will these work on my truck? Anything unusual I need to be cautious about? I remember this being a very simple bolt in operation without any real adjustments. Am I forgetting what goes into this? We did my Mustang back in the 90s and my cousin did most of the work so maybe I'm forgetting that we set the valve lash.

Also, does anyone know about the quality of Summit parts? I'm not building a race engine, I just want a mild upgrade and I figured these parts should be good unless you guys know they are junk.

Finally, if I ever do decide to upgrade the cam, will this cam work (if I have already put in the roller rockers)? Or should I skip the rockers and just put in the cam?

https://www.summitracing.com/parts/sum-k5200

Thanks!

 

These rockers are not a simple bolt on mod but will require you to adjust the valve clearance for each valve. Not really hard if you have done it before but if not then it can be a bit confusing. It's a cheap effective mod.


The cam change is going to be more involved and will cost you more due to the number of gaskets your will need as well as additional parts required when swapping a cam on an old engine. Like timing gears & chain, crank dampener, etc.


Also it can be very involved if you try to do this while the engine is in the vehicle.

 

A new flat tappet cam is going to need new flat tappet lifters.

But if you go through that expense, go for full roller rockers. The trunnion bearings will eliminate a lot more friction than the standard ball type bearing of that cheaper rocker.

A 1.72 ratio rocker will give you an additional 7.5% overall lift compared to the stock 1.6 ratio, so it will further multiply the effects of the new cam. These would be the benefits.

 

Thanks for the info, guys! I will proceed accordingly.

 

i ordered this kit form summit last year when i was thinking of molesting my 76 gran torino survivor car. since than i have traded to a 460 car and i can no longer use these parts if anyone can use them, let me know.
i have 2 separate 4 barrel intakes for the 351-400 one painted black, and the other not. i also have a small 390 cfm 4 barrel carburetor.
i have a high volume melling oil pump that i purchased to go along with this kit as well as an extra set of pushrods, because i wasnt sure if i would need them or not.it also has a new set of valve springs made for the use of this cam and a double roller timing chain set.
the kit number is "comp cams k32-421-8" *the actual cam box says 32-421-8 cam specs are int 270. exh 270. dur @ 0.50: 215 215 lobe sep 110.0 valve lift 0.566 0.566 sn# wl3719-15

if i have to throw a number first, i would love to break even and get what i paid for, for them which was a little over a grand for everything in the kit, including the oil pump and additional set of push rods. but i also realize that for me to break even, it wouldnt be any different than if you went to summit and ordered the same set yourself, so i know that is somewhat unlikely on my part. so lets make a deal...i would hate for these to go to waste, since im not going to use them.
steve.

 

If you want to run roller rockers you have to buy the stud kit and you will have to find the right length of push rod for your motor.

 

yeah, i got 2 different sets of pushrods for it, when i ordered it, but i dont know if one or the other is the right length or not.
i do know that i can no longer use this kit, its never been opened since i bought it, and im just looking for someone who could actually make use of it, instead of it just sitting in my house not being used.

 

I just saw this. We should talk on PM.

 

i wish you wouldve gotten ahold of me last week. i contacted summit and returned the kit in exchange for a similar kit that will go for my 460.

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C'EST la vie! But I'm glad you got the parts you needed.

 

1.73:1 is the stock ratio for all the 335 series engines. Scorpion makes a very nice bolt down full roller rocker, no need to have studs installed. You will need to check for correct pushrod length and may need to shim the rocker arms.

That said - a properly selected new cam installed with a "straight up" timing chain set will be light years ahead of the performance gains of installing roller rockers alone. Over .500" lift you will almost certainly need new springs as factory springs reach coil bind at about .500" (check!).