Author Topic: SOHC Street Build Questions  (Read 767 times)

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SOHC Street Build Questions
« on: August 27, 2022, 12:18:28 PM »
Howdy all! I've been lurking here for a few years, ever since I decided that putting a SOHC in a '72 Mustang and then driving it every day would be a good idea...
So, I'm finally ready to get serious about spec'ing/buying parts and trying to build one (great timing with parts/labor/shop shortages, I know). I'm hoping to get a discussion started on "the art of the possible" - what would it take to build a relatively high-horsepower (around 800?) SOHC engine that could/would live in a true street environment.

Some of my thoughts/needs:
1. Daily driver - 30 minute commute to work over "suburb" streets. Not inner-city stop-and-go, but a few stop lights mixed in with 30mph to 55mph runs. I would probably drive this car 3-5 times a week like this.
2. Able to idle in central Florida 90-100* heat in the summers for 10-15 minutes at a time, and able to run at highway speeds (80mph) at around 2000-2500 RPM until the gas tank goes dry.
3. It probably seems crazy/stupid to build a cammer to do generic street duty like this, but it would be way more fun (at least in my dreams) than something like a Cleveland or 429/460 build).

Car will be a '72 Mustang convertible, Pro Touring build: 5 or 6 speed manual, lowered over either a full frame (like a Schwartz chassis) or with custom-built frame/subframe.
Suspension will be 4-link 9" in back, 4-wheel manual discs, rack-and-pinion, 17" or 18" wheels, mini-tubbed in rear.
I'm talking about true daily-driver status, plus the ability to maybe do some amateur autocrossing or hit the drag-strip occasionally.

So, my current thoughts on a build are:
1. Fuel injected - either individual stacks or a dual-quad style setup. Would prefer a "learning" EFI system due to the wide variety of weather conditions over the year. Not interested in any kind of forced induction/power adders.
2. Thinking a dry-sump maybe? What are the pros/cons of running one on the street in terms of reliability of the sump system itself and the engine
3. Thinking big-cube bore/stroke to make it easier to get (at least close to) the HP I'd like to see.
4. From the reading I've done here, it seems like upper end oiling is a big issue with street-driven cammers. Is there a way to better oil the top end? It sounds like Jay's rocker system (if available?) is the best out there.
5. Kind of a stretch, but also thinking a coil-on-plug setup might be cool - thoughts?
6. Block - I've read good things about both the Pond and Shelby blocks. Assuming both were available, what would be the better choice? I saw a post saying that the Shelby block can be over-bored more and has head studs that go deeper; would that matter in this type of build?
7. What about cams - what would be a good grind that gives relatively decent idle (don't need much vacuum as my brakes will be manual) on the street but could hit the 800HP range?

I'm not opposed to farming out the build, but like doing things myself, so would prefer to do as much as possible (barring machine-work) and learn as I go :-) Though I am hoping to avoid some of the heart-ache CobraCammer went through on his Saleen build (if you're reading this - I seriously admire what you built and how you persevered!)

Thank you in advance for any comments/suggestions/warnings.



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Re: SOHC Street Build Questions
« Reply #1 on: August 27, 2022, 02:14:28 PM »
With the quality parts that are available today from guys like Jay and Robert Pond, your goals are easily attainable. 

To answer your questions in line:

1.  The individual stack EFI stuff has been a pretty big disappointment from what I've seen on multiple engine families. 
2.  Dry sump is completely overkill for a street engine.  It's an extreme expense for little benefit on a street car that's "only" making 800 hp.  A well sorted wet sump system to match your chassis would be adequate.
3.  That's correct.  It's easier to make more horsepower and torque in a streetable fashion (read lower compression, not wild camshafts, etc.) with more displacement.  A 4.375" x 4.250" is the cheapest way to go with parts available off the shelf.  You can go much larger (since you don't have a pesky camshaft in the mid section to get in the way) but it requires custom crankshafts.
4.  Jay's rocker system is the best I've seen, but not available at the last time I inquired.
5.  Eh. 
6.  A Pond cast iron block would be my choice.   I just don't see the benefit of an $8000 block.  I would also use his heads.  Stay away from the other guy who's noted for selling Cammer heads.
7.  Custom camshafts will be the way to go here.  Easily attainable to give streetability and to make big power.
Brent Lykins
Lykins Motorsports
Custom FE Street, Drag Race, Road Race, and Pulling Truck Engines
Custom Roller & Flat Tappet Camshafts
Instagram:  brentlykinsmotorsports
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Re: SOHC Street Build Questions
« Reply #2 on: August 27, 2022, 02:30:57 PM »
That is a big project and expensive have you thought about cost maby dial it back from 11 to an 8. I think 600hp range could give you everything you wanted.


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Re: SOHC Street Build Questions
« Reply #3 on: August 27, 2022, 06:55:01 PM »
I keep threatening to write a book on these engines, based on my own experiences and the learning process I went through as I built and ran them.  One of these days I'll do it.  In the meantime I have the following comments:

- It is my opinion that any engine strong enough to make 800 HP will not work well with a self learning EFI system.  The cam(s) required to make this kind of power will tend to fool the O2 sensor, and the system will not tune itself correctly.  Tuning it yourself is not hard, so don't be afraid of that.  Also, any EFI system will compensate automatically for air density and temperature changes, so weather and altitude changes should not be a consideration in any case.

- I have had excellent luck with individual runner intake systems.  The 585" SOHC that I ran at Drag Week in 2008 and 2009 had a Hilborn mechanical setup that I converted to EFI.  That engine had huge cams (316/316 duration, 286/286 @ .050", 0.720" lift, 114 LSA), and with that induction system it idled reliably at 750 RPM, and made 930 HP, powering the 3900 pound Galaxie to mid 9s at 140+.  It was very livable on the street too; in fact I drove Barry R to dinner with it one night when he was visiting.  It was tricky to set up the linkage, because a TINY throttle opening would increase RPM dramatically, but EFI made it possible to tone down the engine to the point where it was street friendly.

- Dry sumps are great, but aren't needed on the street.  The extra complications aren't worth it, IMO.

- An advantage of the SOHC is that there are no cam lobes in the wedge cam location, so you can stroke the heck out of it.  If you don't mind spending the money on a billet crank, go to a 4.6" or 4.75" stroke to get the cubes.

- SOHCs were designed to run at high engine speeds for extended periods, with lots of oil pressure.  This is why the factory oiling system to the heads worked.  For any street application, or even most drag applications, I run a #4 line from the oil filter adapter to the back of the engine, tee it back there, and feed the oil galleries in the heads through the pipe plug hole in the back of each head.  Plenty of oil that way.

- Rocker arms are the Achilles heel of the SOHC.  My rocker system is the only one that provides full time pressure oiling to the roller wheel that rides on the cam lobe.  All other SOHC rockers require splash oiling.  Again, if you are not running at very high engine speeds, there is not enough splash to keep the needle bearings lubricated, and they will fail eventually.  Think a solid lifter setup in the 1980s, before the manufacturers started oiling them directly.  They don't last.  The situation is better with a very mild cam (like the stock cams), and very low spring pressures, but long periods idling will make those needle bearings give up eventually.  If it's just a drag car, no problem, because you aren't idling in a traffic jam for 10-15 minutes, but a street car has to deal with that.  I build my rockers on a limited basis; I wait until I have orders for four sets, then build them in a batch.  At the moment I can only build the non-adjustable version, because my source for the adjusters and adjuster feet has dried up, but I'm hoping I can find a new source soon.

- I use individual coil packs on my SOHCs, and I'm pretty sure that there are some coil on plug setups that will work.  Bill Conley might know of some; maybe he will chime in here.  The EFI systems I use are capable of firing the individual coils, provided they have the ignitor system built in.

- I like aluminum blocks, for the weight savings and ease of sleeve replacement if necessary.  Pond's block was recently redesigned to make it beefier on the bottom end, so it would be a good choice, and cheaper than a Shelby block.  The Shelby block is really good too; I have four of them and I really like them.

- Cams can be an issue because of the lack of cores.  For a while everyone was out of them.  Pond was going to get set up to get the cores made, so Comp could grind them, but I don't know if that has happened yet.  I believe LSM probably has cams available, but I don't like their grinds that much.  I like Comp's VM series cam grinds much better, because they duplicate the side to side lobe variation seen in the stock cams.  The side to side variation seems a little strange, but it has to do with the geometry of the valvetrain.  In simple terms, if you look at the #1 intake rocker, the lobe pushes against the rocker arm roller wheel to open it.  On the other side of the engine, the #5 lobe pulls up from underneath the rocker arm roller wheel to open it.  This leads to different valve opening profiles on the left and right sides of the engine, if you use the same lobe on both sides.  Ford knew this, and designed the cams to compensate for it.  No aftermarket manufacturer did that until Barry R and I got after Billy Godbold at Comp, and gave him the info he needed to design different lobes for the two sides of the engine.  Of course the engine will still run fine with the same lobe on both sides, but it's not the ideal situation.  Email me and I will send you a list of the Comp grinds that are available.  Comp will still grind these cams, but don't currently have the cores.  You may be able to get them direct from Pond, if he did manage to get the cores made up.

- As low volume manufactured components, it is wise to check all the parts that you acquire very thoroughly before assembling the engine.  Pond is a great source for heads, valve covers, intakes front covers, and the chain drive setup.  I wouldn't buy from anyone else when it comes to the heads.  Also, note that the other components will also tend to come in and out of availability.  You may be collecting parts for a year or two before you can get everything that you need.

Hope that helps, and good luck on the project - Jay
Jay Brown
- 1969 Mach 1, Drag Week 2005 Winner NA/BB, 511" FE (10.60s @ 129); Drag Week 2007 Runner-Up PA/BB, 490" Supercharged FE (9.35 @ 151)
- 1964 Ford Galaxie, Drag Week 2009 Winner Modified NA (9.50s @ 143), 585" SOHC
- 1969 Shelby Clone, Drag Week 2015 Winner Modified NA (Average 8.98 @ 149), 585" SOHC



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Re: SOHC Street Build Questions
« Reply #4 on: August 28, 2022, 12:59:52 AM »
Machsohc - Welcome aboard!  You'll find great helpful people here.  You're taking on a big project, so we'll be living vicariously through you...

On the subject of coil-on-plug for the SOHC, I think I have found a compatible solution.  These fit perfectly with minor modification, and best of all they're inexpensive.  Who ever thought SOHC parts could be cheap?

They're high performance Audi multi-fire coil packs.  If you cut a little bit off the bottom of the steel sleeve, they pop onto the plug and fit perfectly into the SOHC spark plug tube.  I think they look the business too:

I just have them mocked up on my engine now.  I haven't run them yet.  It looks pretty straightforward to trigger them from any of the aftermarket ECU's out there that support coil-on-plug.  Here's the connector pinout for each coil:

Good luck getting going with your project!  Mine has to wait longer, unfortunately.

- Bill Conley

A careful study of failure will yield the ingredients for success.


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Re: SOHC Street Build Questions
« Reply #5 on: August 28, 2022, 08:29:00 AM »
Some one should get ahold of John V. He had a 61 Star Liner with a cammer that saw street duty alot. He sold it a few yrs ago but I did see it and heard it at Beaver Springs R&R. I know John had some health problems after he fell a few yrs ago. He may remember what it took to make it streetable or has records of its build.


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Re: SOHC Street Build Questions
« Reply #6 on: August 28, 2022, 10:55:59 AM »
Thanks all for the great info, suggestions and thoughts. I do know this is a big and expensive project (and I even got my wife's buy-in on the cost). I'm expecting somewhere north of $50k for the engine. People I know point out that I could build a Coyote-type engine making more power, with less maintenance, for way less money, but that's not really the point in my mind. The cammer is such a cool engine and very few people I know even have heard of it, or if they have, they think it's extinct. I've always liked the idea of updating "old" things and seeing what I can do with them. This car will likely be my one and only "build" as I'm getting up there in years and I'm not made of money (part of why I tend to try to do things myself), so I want it to be big and loud and unexpected (if that makes any sense).

So, getting back to the discussion.... I prefer an aluminum block for the weight savings, since this will be a car that (hopefully) goes fast around corners. Big Mustangs are pretty front heavy already.

I was thinking a dry-sump would help with both a lower center of gravity for the engine and thought it might help with oiling, but if the consensus is it's more hassle without providing any real benefit, I'm not married to it. I did note in the discussion about CobraCammer's SOHC build, when Jay was running it on a dyno, it seemed it needed 8+ quarts (I don't remember the actual amount, but I remember it was a lot) when revving. I'm not positive that, in my chassis, an oil pan - even with kickouts - would be able to supply that, but I think that can be worked  during mockup, so not too concerned. If I were to go dry-sump I'd need a place to put the oil reservoir, so that's a negative point.

Regarding rotating assembly - definitely want to get the toughest I can (within reason), so likely yes on a billet crank and top-notch rods.

Bill - thanks for the info and especially the pic! That's exactly what I'm looking for, so will note the info on my parts spreadsheet.

Jay - if/when you get ready to make another set of rockers, I'll definitely be interested. For a "street" build such as this, are there benefits to using the adjustable (i.e. should I wait on rockers in the hope you'll find a new source for the adjusters)? And please write that book :-) I'll send you an email shortly about that and the cams (thank you!). Pond has been at the top of my list for vendors so I'll be contacting them when I'm ready to order. I totally understand that parts can take a couple of years to get in (CobraCammer mentioned that in his first post, I think), and that's fine - I'm expecting the entire build (car, drivetrain, engine) to take 3 years or so. I like to get all my ducks in a row before I start buying parts.

I'm going to spend some time reading the various threads about stroker combos you all have used and see if I can get a consensus on bore/stroke combos and what specific parts to use. I don't mind over-building the bottom end on a motor so I never have to worry about pushing the limits.

Again, thanks for the info/comments/suggestions and keep them coming if you think of something. Hoping this is just the start of a really fun build!


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Re: SOHC Street Build Questions
« Reply #7 on: August 29, 2022, 08:23:54 AM »
I think 600hp range could give you everything you wanted.

I agree.

I’m running an iron head cammer in my 63 Galaxie. The engine has been detuned somewhat from factory specs, has 10.3 to 1 compression, has a 4” stroke to give 452 cubes, and a pair of Comp street cams supplied by Jay. With a pair of 780 Holleys it idles at around 850 rpm, doesn’t over heat in traffic in hot Australian summers, and makes over 600hp. When I floor the throttle in 1st, 2nd or 3rd, it just smokes the tires, and in 4th (Toploader) it just rockets to way past the legal speed limit. I haven’t had it down the 1/4 mile, but it feels like a low 11 second car, not bad for a 4300lb barge.

The point I’m trying to make is, unless you are regularly racing your car, 600hp is more than enough for any street car. Sure, it’s your car and you can build what you like. But on the street, you’d be hard pressed to tell the difference between a 600hp and 800hp car. Just my 2c, please take no offence. I actually commend you for delving into the world of cammers.

Leny Mason

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Re: SOHC Street Build Questions
« Reply #8 on: August 29, 2022, 08:28:15 AM »
Hi, I looked into dry sump but then I thought about the location of a power steering pump, alternator, A/C compressor, mine is supercharged so that takes up a lot of room, Leny's Repair 4062277587 has coil on plugs that fit perfect with needing hold down brackets, this project will be so much fun for You go for it!!


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Re: SOHC Street Build Questions
« Reply #9 on: August 31, 2022, 01:29:15 PM »
Leny and ToddK - thanks for the info and thoughts! Leny - good comments on the dry sump. Space to the side of the engine (and for the oil reservoir) has been a concern when I looked at dry sump systems. I'll be running AC as well (and power rack & pinion). Ultimately, I'll probably mock up the engine in the bay and see what fits best. I won't have shock towers as I'll be installing a coilover suspension, so that helps with room, but I know the cammer is a big beast. I'm a big fan of not making things overly complicated or crowded, so if an oil pan works, it works.
ToddK - Regarding power output - 800 is kind of just a number in my head. From everything I've read, I believe an all aluminum big cube cammer running on 93 octane can make north of 700 with decent idle and road characteristics. At the end of the day, I want day-to-day reliability, some level of every day driveability (note that the Mustang currently is a 3800 lb 5-speed 302-2V with manual drum brakes and no A/C in Florida, so I'm kind of used to living with few modern amenities). It needs to start up (pretty much) every time, drive in traffic without embarrassing me, and run hard when the time and place presents itself. Yeah, 500HP is probably more than enough and 600HP is perhaps silly, but 700+ will put a grin on my face for years to come (and 800 would be amazing) and I just want to see what is possible, then try to build it.  :) I do plan to do some autocrossing/road-course and dragstrip work (for fun).