All Small Six Cam Upgrade and Valvetrain Impacts

[65MustangI6]

I'm rebuilding my 200ci inline 6 for a '65 Mustang with the purpose of using it as a daily driver. I want to increase hp and gain some low end torque (~1,000 to 4,500 RPM range) to meet today's driving standards. As such, I'm looking at a cam upgrade, maybe Comp Cam 260 with 110 LSA or the Schneider 248-56H/110.

My question is related to the valvetrain itself. To start, I have the stock non-adjustable rocker arm 1.5x assembly. It looks like the stock lobe lift was .232 generating a valve lift of .348. If I choose to upgrade the cam the valve lift goes up to ~.42-.44. With the increase in lift, other than the valve springs and hydraulic lifters, do I need to do anything else like change to a shorter pushrod or move to an adjustable rocker arm assembly to adjust for the valve lift increase? I'd like not to make any other changes if possible, but the increase in lift has me concerned.

Any help would be greatly appreciated - Thanks!

 

[Invectivus]

I‘m sure I’ll mess up part of this and get corrected, but I’m pretty sure the dwell radius of performance camshafts are the same as stock, so you shouldn’t need to swap your valvetrain due to the upgrade. You might want to swap to shorter pushrods and/or adjustable rockers depending on whether or not you’re shaving your head to decrease your chamber size.

You might want to be more verbose in what your desired end state is for the car, it does matter, and what all you’re touching in your rebuild in case people have ideas you might not be aware of. For instance, I blew my head gasket, so I took the opportunity to upgrade to a large log head, shave it for 48/49cc chambers, had a port divider braised in, and had the valve guides cut for nitrile seals.oh, and stainless exhaust valves. Since the head is off, it’s the best time to do the cam/lifter swap and install the double timing chain I’ve had for like 6 years. But I’m not swapping to flat top pistons or messing with any other parts of the bottom end. Are you?

Get the falcon performance handbook if you don’t already have it, super handy for laying out different upgrades and their relative values. I have two copies, but I need a third because I can’t find either one ATM…

 

[Frank]

With your modest rpm range (up to 4500) the stock valve components will work- unless there is coil bind. A "small-six" person will have to answer that. The lobe base-circle of the aftermarket cams should be the same as stock, so no pushrod change is needed.
I have upgraded from stock to modest cams, some bigger than the 260 Comp, without changing anything else in the system. I never had a problem with valve float, bent pushrods, etc. The key is keeping the rpm reasonable. High rpm= heavier springs/pushrods needed.

 

[chad]

"...more verbose in what your desired end state is for the car..."
that's my fault as I said 'modest detail" in requesting he post Mon the 28th.
Yes, even tho he;s (post #2) a bronk driver, he's madea point: APPLICATION detail = more accurate/helpful answers (& Qs).

U said: "today's driving standards"... such as?: 'pick up' at the 65 to 75 MPH stage on interstate? access to on ramps? stop light to stop light, etc. Plus 80% of running rpm, octane, hope for MPGs, etc - from this rebuild. I think all U need is frnt disc breaks aahahahaa

 

[wsa111]

I'm rebuilding my 200ci inline 6 for a '65 Mustang with the purpose of using it as a daily driver. I want to increase hp and gain some low end torque (~1,000 to 4,500 RPM range) to meet today's driving standards. As such, I'm looking at a cam upgrade, maybe Comp Cam 260 with 110 LSA or the Schneider 248-56H/110.

My question is related to the valvetrain itself. To start, I have the stock non-adjustable rocker arm 1.5x assembly. It looks like the stock lobe lift was .232 generating a valve lift of .348. If I choose to upgrade the cam the valve lift goes up to ~.42-.44. With the increase in lift, other than the valve springs and hydraulic lifters, do I need to do anything else like change to a shorter pushrod or move to an adjustable rocker arm assembly to adjust for the valve lift increase? I'd like not to make any other changes if possible, but the increase in lift has me concerned.

Any help would be greatly appreciated - Thanks!

Call Jerry at Schneider for a recommendation. The Comp 260 is an antiqued design. I would not recommend it.
The best bang for the buck is get one of my Duraspark 11 distributors with the curve tailored for your combo. You would have to also upgrade to a better ignition box. Check out my listings in the small six for sale section of this forum. Bill questions billythedistributorman@live.com

 

[65MustangI6]

I‘m sure I’ll mess up part of this and get corrected, but I’m pretty sure the dwell radius of performance camshafts are the same as stock, so you shouldn’t need to swap your valvetrain due to the upgrade. You might want to swap to shorter pushrods and/or adjustable rockers depending on whether or not you’re shaving your head to decrease your chamber size.

You might want to be more verbose in what your desired end state is for the car, it does matter, and what all you’re touching in your rebuild in case people have ideas you might not be aware of. For instance, I blew my head gasket, so I took the opportunity to upgrade to a large log head, shave it for 48/49cc chambers, had a port divider braised in, and had the valve guides cut for nitrile seals.oh, and stainless exhaust valves. Since the head is off, it’s the best time to do the cam/lifter swap and install the double timing chain I’ve had for like 6 years. But I’m not swapping to flat top pistons or messing with any other parts of the bottom end. Are you?

Get the falcon performance handbook if you don’t already have it, super handy for laying out different upgrades and their relative values. I have two copies, but I need a third because I can’t find either one ATM…

Thanks for the feedback. In response to my desired end, I'm looking to build a Stage I motor with most of the options as outlined by Classic Inlines. My 200ci block is a '68 (7 mains) that is bored .030 over and the head is a '73 so it has the large log manifold. I'd like to get to a C/R of ~9.3 and I'm working with the machine shop now to cc the chambers and determine if we mill the head, deck the block or use flat top pistons; or more likely a combination to get the compression.

Since the engine is apart and the machine work is getting done, I have the shop balancing the lower end (manual trans), installing hardened exhaust seats and completing a valve job. I'll add a new harmonic balancer and double roller timing chain as well. I figured it was a good time to upsize the cam (mildly since I want to use it as a "daily driver") and install new springs and lifters. If the block and head are compressed to get my desired C/R then I expect to have to deal with the pushrods. Having the non-adjustable rocker arms is where my confusion comes in as I'd like to leave the assembly alone if possible.

Additional enhancements include adding a 2v carburetor using an adapter, change the distributor and make some exhaust manifold improvements.

I did purchase the Ford Inline Six performance hand book, but not the Falcon. It sounds like I should pick up that book as well.

Thanks again for the assist!

 

[65MustangI6]

"...more verbose in what your desired end state is for the car..."
that's my fault as I said 'modest detail" in requesting he post Mon the 28th.
Yes, even tho he;s (post #2) a bronk driver, he's madea point: APPLICATION detail = more accurate/helpful answers (& Qs).

U said: "today's driving standards"... such as?: 'pick up' at the 65 to 75 MPH stage on interstate? access to on ramps? stop light to stop light, etc. Plus 80% of running rpm, octane, hope for MPGs, etc - from this rebuild. I think all U need is frnt disc breaks aahahahaa

No issues, learning as I go

And yes, I live in the Phoenix valley so I'm looking at freeway driving and stop-and-go traffic at times. We also like to get out of town and head to the mountains so power going uphill. Decent MPG on regular unleaded. No drag racing or anything close, street driving only. I'm installing front disc brakes, new suspension and steering to make the vehicle safe and enjoyable to drive.

 

[Jmustang_65]

"I expect to have to deal with the pushrods. Having the non-adjustable rocker arms is where my confusion comes in as I'd like to leave the assembly alone if possible."

You can use either adjustable/non but if you mill the block you might need new pushrods but you won't know until all is assembled then your measure.

 

[bubba22349]

Thanks for the feedback. In response to my desired end, I'm looking to build a Stage I motor with most of the options as outlined by Classic Inlines. My 200ci block is a '68 (7 mains) that is bored .030 over and the head is a '73 so it has the large log manifold. I'd like to get to a C/R of ~9.3 and I'm working with the machine shop now to cc the chambers and determine if we mill the head, deck the block or use flat top pistons; or more likely a combination to get the compression.

Since the engine is apart and the machine work is getting done, I have the shop balancing the lower end (manual trans), installing hardened exhaust seats and completing a valve job. I'll add a new harmonic balancer and double roller timing chain as well. I figured it was a good time to upsize the cam (mildly since I want to use it as a "daily driver") and install new springs and lifters. If the block and head are compressed to get my desired C/R then I expect to have to deal with the pushrods. Having the non-adjustable rocker arms is where my confusion comes in as I'd like to leave the assembly alone if possible.

Additional enhancements include adding a 2v carburetor using an adapter, change the distributor and make some exhaust manifold improvements.

I did purchase the Ford Inline Six performance hand book, but not the Falcon. It sounds like I should pick up that book as well.

Thanks again for the assist!

So to get to a 9.3 to Compression Ratio with a 1968 200 Six block that is a .030 over Bore. One Combo you can use is with the stock 6.5 CC Dished Pistons and than Zero Deck the Block. Used with a FelPro Head Gasket (that has a .050 Crush Thickness), you would then need to Mill the Large Log Head so that you had a 51 CC Combustion Chamber this would bring you right up to a 9.3 to 1 Static Compression Ratio (C.R.) and would have a .050 Quench Distance.

The Stock 1963 1/2 to 1968 Ford 200 Six's mostly all had these 6.5 CC Dished Pistons except for California Emissions models (the original Ford Pistons had a Compression Height of 1.511) setting top down the bore .019 and with the stock Small Log Heads usually at 52 CC's and the Steel Shim Head gaskets (about .022 Crush Thickness) they would have a Quench Distance of .041 with a C. R. of 8.7 to 8.8 to 1.

The problem is that most of the Ford 200 Six replacement Pistons ill only have a Compression Height of 1.5 putting the piston even farther down the Bore at .030 and requires a lot more block Milling to bring it back again. I have recently found out that the Australian Spec 200 Six Pistons (with a 6.5 CC Dish) are available easily right in the USA for about the same price as the other's, this can save some cost of doing so much Block Deck Milling. Those Pistons have a higher Compression Height of 1.530 so this should bring us right near a Zero Deck Height with the stock Block Deck Height or very close. You could also use the Flat Top Pistons for a little more bump in the C.R. though the supply of them seems to have dried up and I have not been able to find them so far. Another option would be to Mill the Block deck so that the pistons are .010 above the deck than you would be right back at the much better Factory 200 Six Spec of a .040 Quench Distance and the head won't need to be milled as much either.

For Mods to the Head you could put a stock 1.75 Inch Intake Valve in them like Ford used starting in the 1977 later Large Log Heads or you could even go up to a 1.80 Inch Intake if you need to replace all the Valves anyway many also use a 1.50 Inch Exhaust Valve to for better Flow.

The best way to do a 2V carb install on a Large Log Head is to do the Direct Mount (the Flat Top Large Logs are best for this Mod), however you can still can get decent results by using the 2V to 1V adapter by opening up the Carb Hole in the intake log to a 2 inch from its current 1 3/4 inch size there are some people even go up to 2 1/8 inch opening. Next you do a nice Radius on the bottom edge of the Carb Hole opening with a good size radius of 3/16 to ¼ or maybe 5/16 inch for those sides leading into the lengthwise of the Log this helps the Air Fuel Mixture to turn the corner into the Log. These two above operations can be done yourself with only a few basic tools. These late Large Log Heads are such a great improvement in air / fuel flow plus those other small changes also help to increase the flow too. The stock untouched Large Log Heads are usually 62 CC's, it works out to a 2 CC reduction for each .010 Mill Cut, so takes roughly a .075 mill cut to bring a stock late model head down to 52 CC's.

X2 there isn't any Problem in using your Non Adjustable Rocker Arms but you will need to get new Shorter Push Rods. X2 yes for sure call Jerry at Schneider for a Cam recommendation. Good Luck on your 200 Six build

 

[fast64ranchero]

I have used the Comp 260 cam and I have to say, I loved it! My 200 bone stock with low compression made 95 RWHP with that cam Terra Yella rockers and a header. (stock 1V carb) that's like 80% power increase as stock RWHP is around 55.
you may have to shim the Towers on the valve train to get the preload correct. Mill the head 0.060" .
If changing pistons look at Silv-o-lite piston 3327H which is a flat top Hyperuetectic piston made for the Aussies. I have used it and it works great for making compression easier.
Good luck on your project

 

[chad]

U say "...Stage 1 motor..." I'd say ur on the II / III line. Go back'n look at the list. Might's well add the very few items/processes as they're a fraction of what you're doing now (ie APR rod bolts'n more). Yes, a RAR increase to 1.7 is very expensive - I'm not suggesting that, just skim the list. Ur basically there anyway~
Thanks for the ask, keep us informed, sounds good...