Stock 360 Block power

[Timmy's Toy]

I have a 68 Dart bracket racer with a 360 in it. Car weighs in at 3,000lbs with my tubby body in it. Tranny is a 727 torqueflite with a 4500 stall converter, 8-3/4 rear with 4.57 gears. I shift at 6500 and run through the traps at 6800. Engine is a Mopar Performance short block with small chamber W2 heads, Indy Intake, and Hedman 1 7/8 race headers. I swapped the hydraulic 509 cam for a solid 557/296 Mopar Performance camshaft. Best run is 11.10 at 120mph. This engine has run for 4 years without a hitch. (knock on wood) It still runs strong but it’s time to tear her down and check out the vitals. Especially since the pistons are hypereutectic and the crank is cast. I would like to upgrade the reciprocating parts to a 408 stroker (all forged parts). I intend to deck the block and use flat top pistons that with the 55cc chamber heads should produce 12.0+ compression. I’m going to have the heads ported completely and the intake matched, etc. With an aggressive .600+ inch camshaft this engine should produce lots of power. My question is: how much power can the stock 360 block take? Will the stock 2 bolt main block handle it? What concerns do you think I would have? I’ve gotten a lots of conflicting advice on this and would like to hear thoughts from A engine racers.
Tim

 

[rumblefish360]

how much power can the stock 360 block take?

They'll take an honest 550 HP without issue. Exceeding this level I go grey on.

Will the stock 2 bolt main block handle it?

Yes, it will. Make year end checks.

What concerns do you think I would have?

If all runs right, little. Things like over reving will create oil cavitation and super stres on the rods.

I’ve gotten a lots of conflicting advice on this and would like to hear thoughts from A engine racers.

You allways will

 

[moper]

Being that this is a bracket car, awith the parts and compression the chances are good that you will exceed that 550hp mark, I would replace the caps (1-4) with billet steel and stud the mains. That, and high quality parts (K1 forged crank and rods.. Not the cast or eagle/Scat stuff) will keep it alive when you're around 600hp naturally aspirated. I think if you are concerned beyond that I'd replace the block. Because once you get into bushing the lifter bore for solid rollers, fitting a girdle, doing caps and studs, and sonic testing, you might as well just spend the cash on a better block.

 

[Timmy's Toy]

What do you consider to be over reving? The rev limiter is set at 7000. I've never exceeded it.

 

[Timmy's Toy]

I do agree with what you're saying. At this time I believe I'm just going to freshen the motor and start looking for a good R3 block that I can build. The R3's have four bolt mains and extra strength throughout. It is my understanding that Comp Cam's has a new roller lifter that does not require the lifter bores to be bushed. Mopar Muscle magazine built a 360 with the new lifters on their latest "old school rebuild" with big compression, tunnel ram, and big cam. Has anyone used them so far?

 

[jefflock]

I knew Hughes has new drop in roller lifters but didn't know Comp had them.

 

[64physhy]

You should use a stud girdle on anything over about 500 HP. 7K is more than I would feel comfortable spinning it, but that's just me. Even with all forged internals and H-beam rods, I don't take mine over 6500.
I agree with jefflock on the lifters, I don't think Comp's are drop in, unless you're talking solid roller.

 

[moper]

You dont bush bores in a race engine for oil pressure alone. You bush to correct the alignment, to equalize power, and stabilize the valvetrain. And those solid body lifters weigh a ton (comparativly speaking) when you need to rev.
You're thiking like I do in regard to the new block. Girdles IMO are a waste of money unless you manifacture and sell them with the possible exception of classes that require a factory block, and even with those there is little improvement in regard to overall lower end strength once the caps are all good material and the clamping force is high enough. If you think you need a girdle, you need a better block.

 

[w2360Duster]

I don't think Comp's are drop in, unless you're talking solid roller.

they do.

 

[Guitar Jones]

Well I've been running a MP short block for ten years. .670 lift flat tappet, small chamber W5's with 12.7:1 and most recently a tunnel ram. All I did besides cut deeper valve reliefs and go over everthing was stud the mains and install ARP rod bolts, I didn't even line hone it or have the big ends of the rods checked, I didn't have time when I built it.

I'm building a .030 over stroker stock block now. It's been tall filled with Hard Block, studded and honed with torque plates. I have a Hughes girdle for it and a .700 lift roller cam for it. I'm also going with 2.08 intakes this time around and more port work. a K1 crank, Eagle H beams and Wiseco pistons for 12.3:1. I expect it to make in excess of 650 HP. Will the block take it? I don't know, we'll find out. I currently spin the motor to 7200 and I expect to do the new engine about the same.

I have done oiling mods to it though. One point you need to check out is if you can really put solid rollers in a 59* R block. As far as I know it doesn't work.

 

[Timmy's Toy]

Okay here is a copy of the Mopar Muscle article, July 2010, "Old School Power" that says there is a new Comp Cams roller lifter that doesn't require modifying the lifter galley with the tube the old way. Here's what they wrote:


"This brings us to the heart of this
endeavor, and that's the camshaft.
According. to believed instructions, a roller
cam is not supposed to fit in this new-or
any small-block Mopar-without some
serious modifications. Since we wanted a
camshaft with lobes that look like they had
no ramps (read: big), a roller was really
the only logical choice for us, but what
about this roller-cam stigma? We wanted
to find out what cam would best suit our
needs, and the best way to do that is to
contact a cam manufacturer. We called
the tech line at Comp Cams, gave them
our specs, and then asked them to make
two recommendations-one for a flat
tappet design and one for a roller design.
Lucky for us, the guys at Comp also let
us know that they have just released (as
of this writing) a new solid roller-lifter
that they said would fit into a small-block
Mopar (PN 8043-16)."

There was a picture in the article of the lifters sitting in the bores with the tie-bar attached. They have fired this motor and run it in the car with no problems that I'm aware of. So if I understand this correctly anyone can run a roller cam in a small block without the pain in the butt mod's. Comments?

 

[rumblefish360]

Not exactly true, there was a thread here showing a big issue with the lifters oil band popping up out of the bore leading to a loss of oil pressure.

the deep lifter bores of the roller blocks and late Hyd. blocks are idea or at least should be for this operation. Otherwise, contact brain (member OU812) for his set up for trouble free drop in lifters.

 

[Timmy's Toy]

The block they used was a late model 340 replacement with the tall and thick lifter bores. I believe and agree with you that an older stock block won't work because of the design and the lifters would or could pop out enough to void the oil pressure. So the article is kinda true!

Yo Fish: Cold and snowy in NY? It was 72 degrees and sunny here today! Sorry buddy, just had to throw the dig.

 

[rumblefish360]

Um, no snow today, cold yes. I didn't venture outside. I work nights outside, so, I'll be chok full later. No worries, been doin it for a carear worth, so dressing right is part and parcel.

 

[RustyRatRod]

Some of the older blocks will work. The problem with the lifter bores was not across the board. If you look at the bore tops, some are chamfered and this causes the oil band to become uncovered on some. If there are no chamfers, the block will usually work.

 

[Timmy's Toy]

I've got an old 360 stock block on a stand in the garage and took a look see. Yup the lifter bores are chamfered and skinny and quite yucky looking. As I look at the pictures of the 340 block that Mopar Muscle used in its build you can see the thick square shape of the lifter bores and understand how they will work with the new Comp lifters. I would not even try them on the old skinny block. So... once again I learn much from sharing info. Thanks too all that responded. I wish you all well!
Tim