[Grimbrand]

Agreed. I will run my stock bottom end up to 6k and shift. Knock wood, it has never let go.

Hold the skinny pedal to the floor until the valves float. Shift. Repeat. =)

 

[66Mustang2021]

I would replace the rod bolts with some ARP bolts.

Unless Summit put non-factory rockers on the engine, the 1.5 is a typo. If they are 1.5 it will reduce the lift and .050 duration of the cam as those are calculated for a Ford based on a 1.6 rocker.

Already planning on changing them to match the cam and heads

 

[66coupe289]

Hold the skinny pedal to the floor until the valves float. Shift. Repeat. =)

My cam is supposed to give up at 5,500 but with AFR 165's it will pull till it hits the rev limiter at 6,200. I expect valve float is not far up the dial.

 

[66coupe289]

Already planning on changing them to match the cam and heads

Make sure you match the rocker stud diameter on the heads you buy.

 

[66Mustang2021]

It's common for a car with a broad, flat torque curve and modest peak power to absolutely stomp a high-horsepower 'peaky' car. When you get to power levels that will smoke the tires at any RPM, then traction - not horsepower - becomes the issue, especially when on the street.

Another thing that's frequently overlooked is power-to-weight. The lightest Hellcat weighs 4428 lbs. With 750 horsepower on tap, that's a very impressive 5.9 lbs per horsepower. But in a 3000 lb Mustang - not to mention some that are as light as 2600 lbs - you only need 508 horsepower to hit that same ratio. That's not a crazy number at all for a built 351, much less a stroker. It's not even exotic, these days. You could also get there easily with a blower on an 8.2 decked block like a 289 or 302 - though for reliability, you might want an aftermarket block.

But keep in mind, while everyone wants big numbers (it's human nature) you need to also consider things like brakes, chassis stiffness, and how well your suspension will handle that much power. Your old classic also won't have a computer that keeps you from doing a Pee Wee Herman and plowing into a sign when you lose control.

As many have said before: How fast can you afford to go?

Yes working on suspension as well, brakes are updated.

 

[blkfrd]

1.7 rockers tend to be noisy and hard on parts. If they're rollers, they are probably fine, but rollers are not as reliable as the old sled types, and they don't even make more power until you're above 5k RPMs anyway. If you are making a reliable street engine, good quality 1.6 sleds are the way to go, usually.

I've had 1.7 rockers for 15 years now. Not loud and not hard on parts. I just took the top end apart after 15 years of being together and the valve train parts including valve guides, springs, etc. are all in great shape.

Yes they do increase valve velocity and acceleration and you have to be sure your valve springs are up to it. Yes they do increase the force required to open the valve since the lever arm is shorter, but an aggressive cam and stout valve springs can be just as hard or harder on the valve train. Higher ratio rockers do have the advantage of increasing the closing force of the valve acting on the rest of the valve train during the closing ramp portion of the cam lobe. IOW, it helps to push back heavy pushrods and/or lifters.

 

[66Mustang2021]

Ford never made nor used used 1.5 rockers on a Windsor, ever. There aren't even aftermarket Ford-designed rockers in 1.5 that I know of. All are 1.6 or higher.

Some genius might've bought Chevy rockers, even though they have the wrong geometry and have a lower ratio than stock Ford. They "fit". But they'd be bad on a Ford head. So either typo, or a really poor part choice!

1.7 rockers tend to be noisy and hard on parts. If they're rollers, they are probably fine, but rollers are not as reliable as the old sled types, and they don't even make more power until you're above 5k RPMs anyway. If you are making a reliable street engine, good quality 1.6 sleds are the way to go, usually.

I'd also love to see what kind of faerie magic made that motor produce 250 horsepower. OE cast iron heads with stock cam, and 8.5 compression? Even with a good 4V intake and carb, and headers, that's essentially a stock 5.0 (NON HO) motor, and those usually make about 180-190 horsepower. The HO version with 9.0:1 compression and a hotter cam produces about 225. Throw in some '1.5' rockers, and they'd be down another 5-10 horses, not up 60...

This is not a dig at you, @66Mustang2021 ! Just annoyance at false advertising!

I not taking it as dig on me, The 2017 motor i have rated at 250hp, new ones at atk site are rated at 240hp. They are dynod. Call atk its there hp99f motor. Thanks for input[

 

[ArizonaGT]

Hold the skinny pedal to the floor until the valves float. Shift. Repeat. =)

…that’s why I‘ll only run solid cams 🤘

 

[66Mustang2021]

Yes working on suspension as well, brakes are updated.

Also as mentioned earlier i was looking for at most mid 300s far as hp. That plenty for me as said especially in a mustang that weighs 2800# Not looking to push 400 to 500 hp. Not a race car just something to have fun with on weekends. Just wanted a little more get up and go. Thx

 

[Grimbrand]

I've had 1.7 rockers for 15 years now. Not loud and not hard on parts. I just took the top end apart after 15 years of being together and the valve train parts including valve guides, springs, etc. are all in great shape.

Yes they do increase valve velocity and acceleration and you have to be sure your valve springs are up to it. Yes they do increase the force required to open the valve since the lever arm is shorter, but an aggressive cam and stout valve springs can be just as hard or harder on the valve train. Higher ratio rockers do have the advantage of increasing the closing force of the valve acting on the rest of the valve train during the closing ramp portion of the cam lobe. IOW, it helps to push back heavy pushrods and/or lifters.

I am glad to hear you say this, because I chose roller 1.7s for my new build, Tracy. lol

However, I have had a lot of friends with 1.7s that sounded a bit clattery. Maybe it's just a matter of ramp rates/cam choice more than the rockers in this matter. =) What kind of rockers did you pick for your engine? And how are the new heads coming along?

 

[ArizonaGT]

I kinda like the clatter 😉

 

[66Mustang2021]

I am glad to hear you say this, because I chose roller 1.7s for my new build, Tracy. lol

However, I have had a lot of friends with 1.7s that sounded a bit clattery. Maybe it's just a matter of ramp rates/cam choice more than the rockers in this matter. =) What kind of rockers did you pick for your engine? And how are the new heads coming along?

Comp cams magnum roller tip rocker arms 1.7s

 

[66Mustang2021]

Comp cams magnum roller tip rocker arms 1.7s

I know u were asking

Comp cams magnum roller tip rocker arms 1.7s

Hit send too quick lol But was going to say opinion on roller tip rocker arms?

 

[Jeff351w]

I ran those rockers in 1.6 for years with no issues on a similarly built setup. Opinions vary, but you should be fine at the power level and RPM you are looking at.

 

[blkfrd]

I am glad to hear you say this, because I chose roller 1.7s for my new build, Tracy. lol

However, I have had a lot of friends with 1.7s that sounded a bit clattery. Maybe it's just a matter of ramp rates/cam choice more than the rockers in this matter. =) What kind of rockers did you pick for your engine? And how are the new heads coming along?

I was in the market for 1.7s back in 2006 and Probe just started making shaft mount rockers then. For a few hundred more than stud mount rockers, I purchased their 1.7 shaft rockers system. I also installed Comp 26986 Beehives at the same time. I've been running this combo for 15 years with my rev limiter set to 7100. I think LGM Racing took Probe's design and is selling them now for almost $1200.

The new Promaxx 180s are coming along. I've done some port cleanup and i'm going to touch up the chambers a bit. I'm going to put the beehives on them also or buy a new set of PAC-1286s and my shaft mount rockers will look real nice sitting on top of a set of aluminums for a change instead of ported Ford iron. I also got some JBA 1-3/4 long tube headers because my Dougs 1-5/8 Tri-Ys are too small to work with the wider ports. The JBAs will work better above 6000 anyhow. All this bigger/better stuff is going to probably extend my rpm range up to almost 7500, but do I do I click the rev limiter up a few notches...hummm. 7K is the new 6K.

 

[66Mustang2021]

I ran those rockers in 1.6 for years with no issues on a similarly built setup. Opinions vary, but you should be fine at the power level and RPM you are looking at.

Ok thanks

 

[GeoffTheGiraffe]

I am running a stock bottom end 91' 302 with the (#35-320-8) Comp cam XE264HR-12 .544/.544 lift with 1.7 rockers and AFR 165 Renegade heads TKO-600 and 3.80 gears. I haven't dynoed it but it feels really strong. It can pull 5th gear up an incline as low as 1500 rpm and pulls to about 6200 rpm (No problem revving it higher). Makes my 2820lb coupe feel like a rocket. It had no problem putting 3+ car lengths on a new Challenger R/T on the highway the other day.

Reading through this thread made me realize that I used the felpro 9333 pt1 headgaskets and completely forgot about quench and the deck clearance. The headgaskets are .047 compressed as well but I haven't had any weird detonation issues other than the engine liking 24* base timing. Would it be worth tearing the engine down just for the headgaskets? Probably not, but if I decide to swap out my lifters I'll be forced to remove the heads and I'll do it then.

For now the engine runs great, makes enough power to blow some modern cars out of the water, and is as well mannered as stock. I think the you'd find the combo quite satisfying especially with the proper quench and some nicer pistons!

 

[66Mustang2021]

I am running a stock bottom end 91' 302 with the (#35-320-8) Comp cam XE264HR-12 .544/.544 lift with 1.7 rockers and AFR 165 Renegade heads TKO-600 and 3.80 gears. I haven't dynoed it but it feels really strong. It can pull 5th gear up an incline as low as 1500 rpm and pulls to about 6200 rpm (No problem revving it higher). Makes my 2820lb coupe feel like a rocket. It had no problem putting 3+ car lengths on a new Challenger R/T on the highway the other day.

Reading through this thread made me realize that I used the felpro 9333 pt1 headgaskets and completely forgot about quench and the deck clearance. The headgaskets are .047 compressed as well but I haven't had any weird detonation issues other than the engine liking 24* base timing. Would it be worth tearing the engine down just for the headgaskets? Probably not, but if I decide to swap out my lifters I'll be forced to remove the heads and I'll do it then.

For now the engine runs great, makes enough power to blow some modern cars out of the water, and is as well mannered as stock. I think the you'd find the combo quite satisfying especially with the proper quench and some nicer pistons!

Wow sounds almost identical to what im going to do with my motor. Only have 3:23 resrend right now. Makes me excited to get my build going and see what she can do. Thats col the power you are getting out of it and especially that urs well manneted as stock Thanks!

 

[66Mustang2021]

AFR 165 heads, rollers, comp cam and Weiand intake made my car run completely different/better. You're going to be smiling ear to ear and that's better than numbers on paper. Good luck with the install. (I'd guess 75 to 80hp crank gain if I had to)

Are you running a 600 cfm carb? Have you dyno'd you motor? TIA