Let's talk about the forbidden fruits...SBC

Just got back from the machine shop where I had dropped off my old high school motor a std. bore 327.
After inspection it looks like I may have to turn the crank a little....well a lot. My uncle owns the shop and he swears that a Forged Steel American made small journal crank will only lose 4% of it's original strength if it is turned up to .040" I had never heard this but I have no reason to doubt it. He also says that the cranks were overengineered by double the rated requirement.


So what this brings me to is theis motor is being built for my shop truck, the 36 we have discussed recently. If this carnk should render itself too far gone I though about jerking the 283 down and stealing the crank out of it, thus creating a 302. Anyone ever had a 302 in anything?(not Ford 302's) Just wondering what the power band, pulling cahracteristics etc would be? Oh yeah, I'll prolly throw in some 6" rods and a set of Vortec heads to boot.

Thanks

 

I agree that the metal lost in going down is pretty trivial, and certain well-known builders actually advocate (on stock based cranks) turning them way down in order to allow good fillets to be cut, the benefits of the fillets greatly outweighing the loss. The weak point MAY be the bearings--some way undersize bearings have way thick babbitt and stuff on them, a weakness. Good ones have thicker shells and normal thickness bearing material.
And why would SBC's be considered forbidden or non-trad?? In 1955, they got some dissing--"Those tin rockers will never last..."--for about two weeks. After their first appearances in street and strip races against other bigger V8's of the day, they INSTANTLY became fully accepted, and rodders were standing in line to buy the first ones to hit the junkyards. For folks who could't afford to buy a new one from the dealer, junkyard engines were actually scarce up to 1960 because so many people wanted them. They are the true heirs to the flathead.

 

my dad has had a couple dz 302s. one had the duntov cam, the other had the off-road racing solid cam. both cars hauled ass, got shitty mileage, the off road cam would burn your eyes in traffic, but was fast. my mom drove that z everyday for 7 months!

 

The original Z/28 was a 302. They didn't do too badly for themselves. Mark Donahue and Roger Penske got a couple of them to run OK.

 

6" rods in a shop truck ? Waste of money. The 302 will not produce the torque of a longer stroke engine so a deeper rear gear will be a good idea. Perhaps an overdrive behind it ? If it was mine I'd go conservative on the engine and spend what I saved on an efficient driveline.

 

302's turn tight and haul the mail ............if you turn the RPM's. Very little low end torque and are very sensitive to gear changes.

I have had several. 69 RS Z28, a .125 over 283 in a 55 150 series 2 door sedan and a 327 with a 283 crank in a 32 Ford.

I would most likely find another 327 crankshaft or find a large journal 350 crankshaft that needs turning and turn it down to fit STD. in the early block.

 

The crank may be salvageable......why do you think the 6" rods would be a waste? The ratio should help the motor live longer, right? They aren't much more than having old ones sized, pressed off and on...ya know? I have a 3.55 gear and a TH -350 in it now.

 

Souns more like a Drag Thang Root- Id use a 350/with RV cam in it- in the shop truck and save the short stroke one for a lite car.......

 

grumble grumble grumble...350

 

<font color="green">"Forbidden Fruits"

I think you just landed on a name for the DRAG-N-FLY pit crew. </font>

 

The only substitute for cubic inches is cubic dollars.If you can get .040 under bearings,go for it.Or get a 350 crank.

 

Shorter rods will give more torque at lower rpms because of the increased rod angle.Longer rods will show more HP at higher rpms.

 

Do the early SBC's have "Tuft-Riding?"
A nitric acid hardening process - I think - that made the crank very tough down to about .015 below the surface.

The early Oldsmobiles did and I believe the Nailhead and Caddy engines did as well.
Which made a crank turned more than ten-ten (.010 rods and .010 mains) less than desirable.

Desirable or not, more than a few whacked .020 off the cranks and they seemed to live ok in mild engine in a street environment.

I wouldn't worry about 6" rods either.
Just do a quality rebuild on it and enjoy it.

 

OK, I'll check into the 6" rod deal...maybe I'll save my money......

 

Hey ROOT, I'd save the high winding little motor for a race car, build a nice super torquey 400 sbc for the truck, and tell everyone it's a 327. People are dumb, they'll never know the difference.

 

A few years ago, I slapped together a 301.59 from a 283 with 0.125 overbore and slipped it into a 53 ford pickup. I would have realized a lot more of the little winder's potential if I'd put it in a lighter car and put a longer stroke engine in the heavy pickup. Use of a 350 turbo with a stock stall converter hurt me too. Still, performance was pretty good on the bottom end but it was a fargin animal above 3500 rpm. I have another 283 block and steel crank saved away for a lightweight project someday... maybe a modified.
And with the 3" stroke, the stroke to rod length ratio is favorable. 301-302 pistons for a 3" stroke are hard enough to get....imagine buying custom pistons for a 6" rod.

 

build the 327 fuck the cubes. 6 inch rod or 5.7 it don't matter the 283 amd 327 will rev. and thats what make those motor great.

 

The crank should be fine, and if I remember right the first, SBC cranks to be tufftrited were 302's and LT1 350's, your 327 shouldn't be. Also since you are putting this motor into a pick up the lack of low end torque may be an advantage as far as traction is concerned if you run it hard. Smoking the tires for a block under WOT may not be what you want in a regularly driven truck which is what will happen with a long stroke torquey motor, but you knew that(OK so I want it but I'm not practical). Lower gears would definitely be a good idea with a destroked engine, even my 327 could use something lower than the 3.36 it has now. Just don't run a powerglide with a stock converter.

 

I had a set of 3.36 in it and with the rebuild I will swap to a 3.55 in a 9 inch. I have a 57 pass car in it now. Hmmmm......327 maybe the Fly needs some more umphhhh.....??

 

Put a 4.10 gear in it and run a 700R4.

 

That's a thought. I would have to fab new tranny mounts but the o/d would be nice.

 

The bore/stroke ratio of a 302 is better suited to high revs. For a shop truck, I bet you'd probably be happier with more low-end oomph.

Like several previous posts recommended, you might consider trading your hardware to a racer in return for a 350 with an RV cam. Or go to a junkyard- you can't spin a dead cat around your head without hitting a 350...

 

Well, when I say shop truck...I mean it is parked up next to the shop after dark....

I may go the way of the goldchainers...dang. But if I do it'll have to have aluminum heads.

 

I had never heard before that that a shorter rod would give more torque at any RPM range. My understanding was that the longer rod was always better because it results in more dwell time at TDC. The Chev 302s were overbore engines that made good peak HP, for a truck, I would go with a 350 or even the 400 the other guy mentioned. Pistons for that 302 are gonna cost you and I don't know if they even still make them, especialy with the correct compression hight for a 6" rod.

 

The pistons are the same as a 350.
It's a327 with a 283 crank but we have decided to nix that idea anyway. That motor is a backup motor for the Fly now.

 

let's go back to the vortec heads - could anyone give me a complete rundown on these? What years they were made, having to use the vortec intake, etc.? I don't know anything about the newer chevy stuff but these heads sound like they may be the way to go- Thanks

 

Don't forget that yes the bore is the same on 302,327, and 350's but the compression heights are different. The 302 has the greatest compression height, 327 next and then 350.
You can figure it. 9.025=((Stroke/2)+rod length+pch+deck clearance at TDC). You can change the deck height accordingly if you mill the block, say to 9.000 and find your desired piston compression height with a given clearance. For example a 327 with .025 deck clearance on a stock deck height and 5.7 stock rod, 3.25 stroke would need a piston compression height of 1.6750in.

 

Dan, I wouldn't even mess with salvage yard vortecs. You can buy a brand new assembled set for 400 bux. Ready to go. The intakes are different and you need a bolt kit as well.
I think the vortecs came out around 96.

 

shoot for 400 bucks a used set isn't even worth fucking with! Do you know what lift the springs are good for, what size valves they use, what they flow etc.? Sorry if these are simple, obvious questions but I really know nothing about the new chevy stuff. Will headers from my old heads work, are they center-bolt valve covers? Thanks for the help, from what I have heard these would make really good street performance heads, I am leary to try to port and polish mine for fear of actually hurting flow due to no flow bench or experience.

 

http://www.paceparts.com/product.asp?0=243&amp;1=246&amp;3=1023

<font color="green">They are on sale for 249.50 each.

Where are these $400. jobbies ROOT

Iive got them on the 41.

P.M. me with any questions so the TRAD Gestapo doesn't burn our houses down.

RASHY </font>