Lykins Motorsports 347SBF Build...

[blykins]

This build belongs to a fellow KY-resident. I would consider this guy pretty blessed, as he doesn't have just 1 Cobra, but 2 Cobras and a Daytona Coupe. All of them are FFR builds, and I'm lucky enough to provide the mills for all of them.

One Cobra gets a 427FE, based on a Pond cast iron block, Pond heads, a factory 427 crank, and a Performer RPM intake.

The other Cobra gets a 527ci Cammer, based on a Pond block and Pond SOHC heads.

The highlight for this thread is the engine for the Coupe, a 347 SBF. It's based on a factory Ford block at a 4.030" bore size. Scat 9000 series 3.400" crankshaft, with Scat 4340 5.400" rods, and SRP flat top pistons. The cam is a custom Comp Cams hydraulic roller piece, 230/236 @ .050", with a hair over .600" lift, on a 112 LSA.

Induction comes by the way of a pair of RHS aluminum heads and a FAST EZ 8-stack setup. The plan is to dyno with a Victor Jr intake manifold and a Quick Fuel 650 at first, then to switch over to the EFI piece for a comparison and extra data. I like data.

Oil pan is an Aviaid Daytona Coupe pan, and I contacted Nick Acton about building me a set of Coupe replica valve covers. It's gonna be a sweet little engine.

Gratuitous block shots....





It's been align honed with ARP main studs, bored and honed with torque plates, and square decked. Ford semi gloss black paint, brass freeze plugs, and Durabond cam bearings.

More pics and info to come.

[ERA Chas]

This cam would work with Webers also, correct Brent?

[blykins]

Yep......

[Chaplin]

I guess I need to follow this one.

[blykins]

Plan is to get the majority of the short block finished today. Got a sick wife and a sick kid, so I may have to multitask today.

I did send the heads out to Keith and had him massage them. We went from 282 cfm @ .600" on the intake side and 184 @ .600" on the exhaust side to 291 @ .600" on the intake side and 220 @ .600" on the exhaust side. All of that was done by short side and bowl work, no increase of the port CSA, which is what we want. We want velocity as well as flow.

Peak numbers were 298 @ .700" and 226 @ .700".

[blykins]

Well, I got a good bit accomplished today. Heads are assembled and ready to go. Crank is in, cam is in and degreed, and got 4 pistons/rods knocked in. Rod side clearance was too tight, so I had to drop the other 4 rods off to have them surface ground.

Anyway, pics....













Install height was 1.800-1.810". Springs came in at 145 lbs seat, 375 lbs open at that install height. Camshaft was degreed, crank gear stuck on 2 deg advance keyway, ICL was 105.5 degrees, 112 LSA.

[blykins]

Still not there yet, but sneaking up on it. Had to throw the 8-stack on there to see what the final product would look like.

I spent about an hour today going through pushrod lengths in .025" increments. A common misconception is that the pattern on the valve stem needs to be dead-centered on the valve stem. What you really need to look for is a narrow pattern, which indicates that you are not losing valve lift to unnecessary rocker arm travel. Even if the pattern is to one side of center or the other, I'd rather have a narrow pattern.

Finally got it dialed in. Lift at cam lobe was .375". That calculates to .601" with a 1.6 rocker ratio. Kept changing pushrod length with a dial indicator mounted on a spring retainer and got it to .596" lift at the valve.

Going to hit it with a Victor Jr intake to begin with. Got it mocked up today and it fits perfect without an intake gasket, so the intake flanges will need to be whacked about .065". Not uncommon...

I also pulled the throttle bodies off the Inglese setup and checked port alignment. It fit and lined up very well with the intake gasket. It's very important, of course, that the intake manifold angle matches the cylinder head angle (no leaks), but it's also important that the ports are lined up. If you look down an intake runner and see cylinder head, then that's not a good scenario. The air/fuel charge will literally hit a wall as it's trying to get to the valve.

So....

Waiting on pushrods, waiting on the period-correct valve covers from Nick Acton, and have just a few more assembly things to do.

[undy]

Originally Posted by blykins

This build belongs to a fellow KY-resident. I would consider this guy pretty blessed, as he doesn't have just 1 Cobra, but 2 Cobras and a Daytona Coupe. All of them are FFR builds, and I'm lucky enough to provide the mills for all of them.

One Cobra gets a 427FE, based on a Pond cast iron block, Pond heads, a factory 427 crank, and a Performer RPM intake.

The other Cobra gets a 527ci Cammer, based on a Pond block and Pond SOHC heads.

The highlight for this thread is the engine for the Coupe, a 347 SBF. It's based on a factory Ford block at a 4.030" bore size. Scat 9000 series 3.400" crankshaft, with Scat 4340 5.400" rods, and SRP flat top pistons. The cam is a custom Comp Cams hydraulic roller piece, 230/236 @ .050", with a hair over .600" lift, on a 112 LSA.

Induction comes by the way of a pair of RHS aluminum heads and a FAST EZ 8-stack setup. The plan is to dyno with a Victor Jr intake manifold and a Quick Fuel 650 at first, then to switch over to the EFI piece for a comparison and extra data. I like data.

Oil pan is an Aviaid Daytona Coupe pan, and I contacted Nick Acton about building me a set of Coupe replica valve covers. It's gonna be a sweet little engine.

Gratuitous block shots....



It's been align honed with ARP main studs, bored and honed with torque plates, and square decked. Ford semi gloss black paint, brass freeze plugs, and Durabond cam bearings.

More pics and info to come.

Brent, just a question on the Pond engine. I thought, even with clearancing, the Pond block was limited to a 4.25" stroke. That coupled with the max recommended overbore limits it to a 496. That was one of the main reasons that people went with the Shelby block. It was capable of a 4.5" stroke.

Give up the beans on the that beast!

[blykins]

The pond blocks will take a 4.375 stroke without issue. 4.500 stroke cranks are generally reserved for cammers because the rods hit the camshaft. The cast iron pond block will take a larger overbore.

Honestly, I have never seen the need for a Shelby block, unless the name is important.

[Rick Parker]

Brent is this to be neutral balanced?

My own upcoming (long in the planning) will be, however in can't recall if the McLeod Auminum flywheel that I have used for many years has a removable weight???? Current production does but 20 years ago???

[blykins]

This one is not. It's not a high rpm engine, nor will it be a high hp engine, relatively speaking.

On a $250 crankshaft, having to add $100-200 worth of metal just isn't cost effective.

Spent another 30 minutes on the rocker arm geometry, just wasn't happy with it.

Went through a couple more iterations with the pushrod length checker and got it to where I didn't lose any valve lift.

FWIW, a 6.225" pushrod lost .005" worth of lift at the retainer. A 6.300" pushrod didn't lose any, and the pattern was good, just a little past center on the valve tip.

Good retainer to rocker arm clearance. Check.

Good pushrod to rocker arm clearance. Check.

[601HP]

Originally Posted by blykins

This one is not. It's not a high rpm engine, nor will it be a high hp engine, relatively speaking.

On a $250 crankshaft, having to add $100-200 worth of metal just isn't cost effective.

Spent another 30 minutes on the rocker arm geometry, just wasn't happy with it.

Went through a couple more iterations with the pushrod length checker and got it to where I didn't lose any valve lift.

FWIW, a 6.225" pushrod lost .005" worth of lift at the retainer. A 6.300" pushrod didn't lose any, and the pattern was good, just a little past center on the valve tip.

Good retainer to rocker arm clearance. Check.

Good pushrod to rocker arm clearance. Check.

Your attention to the smallest details and values is satisfyingly noted!

David

[undy]

Originally Posted by blykins

The pond blocks will take a 4.375 stroke without issue. 4.500 stroke cranks are generally reserved for cammers because the rods hit the camshaft. The cast iron pond block will take a larger overbore.

Honestly, I have never seen the need for a Shelby block, unless the name is important.

Thanks Brent!

Darn, should went with a 4.375" stoke in mine. That would have helped my HP deficient FE.

I'm spoiled by my LS7...

[blykins]

Throw some more cam and head at it, it will wake up more.

[undy]

I'd like to see some FE heads flowing about 420 cfm on the intake @ 0.650" lift. That would free things up.

[blykins]

Sounds like you need some pond cammer heads.

Keith's stage 3 stuff will go 370 cfm...

[undy]

Sure don't have $30K+ to spend on the SOHC conversion.

Is that 370 cfm at an reasonable lift for an hydraulic roller (.650")?

I have his stage IIs.

[blykins]

Nope...at about .750".

You need some pond heads.

[Cobra #3170]

Originally Posted by undy

I'd like to see some FE heads flowing about 420 cfm on the intake @ 0.650" lift. That would free things up.

So would I, but we need someone to cast a head with the intake valve moved
toward the center of the cylinder. You would need new everything and the volume would not justify the investment.

[Chaplin]

Brent,
What are your predictions for this one?