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307 Stroker

 
ethelkilledfred-#001 ethelkilledfred-#001
New User | Posts: 37 | Joined: 05/10
Posted: 07/18/11
05:04 PM

This has been discussed over and over. Here is an 04 post on CC about a 307 build-

Chevy 307 engine
http://forums.carcraft.com/70/666166/general-car-craft-technical-discussion/chevy-307-engine/index.html

and 2011 thread-
I want 12s
http://forums.carcraft.com/70/8768812/chevrolet/i-want-12s/index.html

I myself would go 383, but that does not mean you can't make power with a 307 if you throw money at it.

John Becks advice...
"This combo has already been proven to be able to make power."



John Beck placed 3rd in the PHR Engine Masters Chalenge with a 307 based 365 motor 556.3 Hp and 518 'lbs of Tq. Becks motor was the most streetable out of them all... PHRs. Joe Sherman is the guy who won with a 350 based 365 motor 604.1 peak hp & 528 Tq

Here is how John Beck built a 307 stroker-

Serious Strategy
John Beck Aims for the Engine Masters Challenge
From the February, 2009 issue of Popular Hot Rodding
By Scott Parkhurst

http://www.popularhotrodding.com/enginemasters/articles/chevrolet/smallblock/0207phrbeckem/index.html

0207Phrbeckem17z
"I'm going to run something a little weird for this deal. I want a smaller bore and a longer stroke to try and keep that curve high all the way from 2,500-6,500. That's not easy to do, but I'm running a Chevy 307 block bored to 3.935 inches, and a SCAT crank at 3.750-inch stroke. That's 365 cubes, so it'll sneak in under your 366-inch limit."


0207Phrbeckem01z
Who'd have thought it? A tired old 307 Chevy block is being prepared to take on all comers. It'll need some help first. The funniest part of this is the truth--this block was actually left at the shop as worthless scrap by a customer.

0207Phrbeckem02z
The mains are being readied to accept a set of four-bolt main caps and ARP main studs. That should be plenty of insurance to support the 550-600 horses John Beck figures his small-block will make at peak power. It's the combination of the small (3.935) bore and longer stroke he's really after.

0207Phrbeckem03z
The crankshaft is also a key player. Checking in at 3.750-inch stroke, the crank comes ready to play out of the box. John says "SCAT stuff is really nice as-delivered. They clean up all the counterweights for aerodynamics, and the oil holes are nicely chamfered."


0207Phrbeckem04z
Don't mind the protective coatinng. Look at the radius in the rod journals and the oil hole treatment. "This stuff is ready to go. SCAT cranks are a good deal, and the quality of the parts keeps getting better. You can't beat this for the price."


0207Phrbeckem05z
The pistons are from JE and will be installed with zero deck clearance. The flat-top design, when teamed with a 60-70cc chamber, should result at around 10-10.5:1. Piston weight should come in at about 400 grams. John has a bit more work to do on the pistons, including gas ports and revised shaping on the valve clearance notches. This is not the actual piston that will be installed in the engine (they were still being made when this story was done), but they'll be very close from a design standpoint.

0207Phrbeckem06z
Ring thickness on the top and second ring will be 1.5 mm, while the oil ring will check in at 2 mm. The distance between the rings will be left up to JE. John has consulted with them on what he needs this engine to do, and he's relying on JE's capable engineering to determine the best-possible ring placement on the piston to achieve his goals.

0207Phrbeckem07z
Hastings rings were chosen for this engine. "It's not necessarily a quality thing in this case. I researched the different ring diameters out there, and this Hastings ring is actually for a Subaru. It's thin, light, and the right size for my bore. If other engine builders fail to look at import listings on aftermarket parts, they are missing out on a wide selection of well-engineered parts." says Beck. The stock-replacement import parts are often less-expensive than comparable "custom" aftermarket parts in these special sizes. There's a tip for those of us looking at oddball bore sizes!

0207Phrbeckem08z
John prefers to use Clevite 77 bearings. "The sizes are right, they wear well, and they offer a wide selection of over- and under- sizes. Quality and consistency are important in building performance engines, and Clevite delivers."

0207Phrbeckem18z
The connecting rods are made by Howard's Racing Cams (HRC) of Oshkosh, WI, and tip the scales at 550 grams. The 5.7-inch "Sport Lite" connecting rods are an I-beam design, more like factory rods than pricey aftermarket H-beam units. They are light, strong, and affordable. They ship with bronze bushings in place, ARP 7/16-inch capscrew bolts, special heat-treating, and are clearanced for strokers. They are also shot-peened and machined with alignment dowels in place (so the caps don't move) and are black-oxide coated. While Howard Cams claims these rods are good to 500 hp, Beck knows they can take a bit more.

0207Phrbeckem10z
The cylinder heads are of critical importance, and John Beck is leaning toward Pro Action iron heads. Of course, he looked over the many available head possibilities, and while Pro Action was the first name he mentioned, it wasn't the only one.

0207Phrbeckem11z
"I've got a really good set of aluminum Dart II heads here in the shop--I'll probably try them, too. But, I've got to believe that the iron heads will keep more heat in the chamber and make more power. Those Darts flow like crazy, though. I'll try them both with the cams I've got in mind, and whichever works best is what I'll send in. I'm thinking it'll be the Pro Action parts."

0207Phrbeckem13z
The valvetrain components are mostly COMP hardware, including the valvesprings and retainers. "The lifters, pushrods, and all my stuff will be from COMP. The cam specs are still undecided, but I'm looking for something around 240 at .050 inch of lift, but I want the duration to be short. The short duration will leave the intake valve closed longer to more-effectively fill the cylinder through the big ports and valves."

0207Phrbeckem12z
"The chambers will end up at 69 to 70 cc. With 10.5:1 compression or so, I figure this little motor will make really good torque down low, which is what I'm after. I still think the power will climb steadily up to 6,500, but with the smaller bore and the longer stroke, I'm hoping to make more grunt down low and have my curve start at a higher power level than the other builders. If I'm shooting for area under the curve, this is the best way I know to increase that area, beyond adding more cubic inches."

0207Phrbeckem14z
The rockers will be 1.6:1 ratio COMP cams "Magnum" style roller-tip units, shown here on a Ford mill in Beck's shop. Beck told us, "They're affordable, light, and strong. You can see that budget is a bigger part of this buildup than many would expect. This engine is headed into a street rod once I win this Challenge with it. I'll leave it just the way I'm building it, except for the cam. I'm planning a really aggressive cam design, one I feel might be too radical for the street. The dimensions aren't too crazy, but the ramps are. I'll make life easier on the valvesprings once the Challenge is over."

0207Phrbeckem15z
The valves filling the heads will be race-proven Ferrea stainless components in 2.08-inch intake and 1.6-inch exhaust diameters. "I'll have them coated, too--along with the piston tops and the combustion chambers."

0207Phrbeckem16z
John chose a Dynagear pump to pressurize the oiling system. "I've used plenty of them. They work great."  
-

Brotherhood of Street Racers

My Space Brotherhood of Street Racers
http://www.myspace.com/brotherhoodofstreetracers

BSR-International
http://bsr-international.ning.com/

ethelkilledfred-#001ethelkilledfred-#001

3836bbl 3836bbl
Enthusiast | Posts: 407 | Joined: 11/10
Posted: 07/19/11
02:22 PM

Great post EKF, good read for all...  
"Fill Your Library Before Your Fill Your Garage"  3836bbl alias Budnicks

ethelkilledfred-#001 ethelkilledfred-#001
New User | Posts: 37 | Joined: 05/10
Posted: 07/24/11
12:23 AM

Icon Quote3836bbl:
Great post EKF, good read for all...

Thanks  
-

Brotherhood of Street Racers

My Space Brotherhood of Street Racers
http://www.myspace.com/brotherhoodofstreetracers

BSR-International
http://bsr-international.ning.com/

ethelkilledfred-#001ethelkilledfred-#001

gtomustang gtomustang
Enthusiast | Posts: 457 | Joined: 06/09
Posted: 07/28/11
05:18 AM

I wonder what the cost of those custom slugs was...maybe $500? More? Another way to 365 cid is to offset grind the crank down to pre-1968 connecting rods, and bore a 4" block .03 over. But I'll guess the cost comes out the same, or at least close...  
Just because you can't do it...doesn't mean its impossible

gtomustang gtomustang
Enthusiast | Posts: 457 | Joined: 06/09
Posted: 07/28/11
12:47 PM

The other musing I forgot...would a 305 block take that overbore?  Then you could get a block whose lifter valley is set up for rollers...or maybe even go for a 4" stroker crank. You then could buy a SS Monte Carlo, and not have to throw the engine out...  
Just because you can't do it...doesn't mean its impossible

gtomustang gtomustang
Enthusiast | Posts: 457 | Joined: 06/09
Posted: 07/29/11
08:01 AM

Now to bump that clothing ad off...a 4' stroke I believe makes a 388cid.  A Pontiac 350, say by comparison, could also take a 4" stroke easy, have long connecting rods, and make 383cid with a deck that can take 455 heads.  Not to pick on the 307 combo, I think its a great idea, but I'd love to see a pursuit of other orphan engine combos...crate 350's are just kinda boring after all these years.  
Just because you can't do it...doesn't mean its impossible

ethelkilledfred-#001 ethelkilledfred-#001
New User | Posts: 37 | Joined: 05/10
Posted: 08/09/11
07:11 AM

Icon Quotegtomustang:
Now to bump that clothing ad off...a 4' stroke I believe makes a 388cid.  A Pontiac 350, say by comparison, could also take a 4" stroke easy, have long connecting rods, and make 383cid with a deck that can take 455 heads.  Not to pick on the 307 combo, I think its a great idea, but I'd love to see a pursuit of other orphan engine combos...crate 350's are just kinda boring after all these years.

You can turn a 305 to 356 with just a .030 bore.

http://forums.chevyhiperformance.com/70/8353312/general-discussion/350-the-hardway-305-block-stroker-crank-500hp/index.html

350 the hardway-305 block+stroker crank=500hp
Parts are plentiful

305 block .030
5.565 rods
Vortec Heads $329.95 ea
Mellings 22400 copy of the Off Road 140 Chevy cam $72.00
Speed Pro ZL2486F30 - Speed-Pro Power Forged Pistons $375.60
SCAT Crank 435086 Forged 4340 Steel, 4.000 in. Stroke, Chevy, 350 $660.95

Heads machined to .520 lift
Heads get milled to 52cc chambers
Pistons get milled .100 = 0 deck
Crank gets counter weights cam cut to clear pistons
Add Mallory to make up for cam cut.

930 dp Holley
Victor Jr
11.5:1 comp
1.94 int, 1.65 ex
H-11 valve springs
Main Cap Girdle

Add 300 shot for @800hp 305 stroker mill. Forged crank and forged pistons can handle a 300 shot  
-

Brotherhood of Street Racers

My Space Brotherhood of Street Racers
http://www.myspace.com/brotherhoodofstreetracers

BSR-International
http://bsr-international.ning.com/

ethelkilledfred-#001ethelkilledfred-#001