what can be done to a 360 for strength

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The biggest problem with the small block mopars are the main webs between the cam and the crank. They are not strong enough to support much over 600 - 650 HP. you will find people out there that have made more power than that and had no problems and some that haven't even made that much and had big problems. Main cap walk and the block its self are the biggest issues. A good main cap system (pro-grams) or something similar with studs and a good balance job are highly suggested.

I'm surprised at your findings. I've seen these problems with B/B but never a small block. I've never seen a small block pull a main web out like a B/B? Any pics? Split cylinder wall possibly.
We've run boosted ones for years with no failures, Yet.
Doug

Posted By: TheOtherDodge

Re: what can be done to a 360 for strength - 12/13/13 04:27 PM

Lightest rotating weight possible and keep the RPMs down.

Posted By: deaks

Re: what can be done to a 360 for strength - 12/13/13 05:43 PM

No offence Mike but my comments were meant for the OP. Lol
Mick

Posted By: qwkmopardan

Re: what can be done to a 360 for strength - 12/13/13 06:07 PM

Use ARP or stock head bolts. Use head studs and you will blow head gaskets. If you insist on head studs, turn the dia. between the threads down to 7/16" and they will work. Cometic gaskets and 13.5 to 1 will work fine. The eng. in my Demon has 1800+ passes and still the same head gaskets, with 13 to 1 CR. Stock block, no fill and center 3 caps are Pro-gram 2-bolt caps. Crank and pistons have never been removed from the 1973 360 block, for all 1800+ passes. Car runs high 9s and a best of 9.68, on 110 oct. gas, at 3050 lbs. with a crank trigger and 28* timing. Also a flat tappet cam and production cast iron cyl. heads. Build a good sm. block and you will never need to switch to a big block.

Posted By: Thumperdart

Re: what can be done to a 360 for strength - 12/13/13 06:56 PM

FWIW I know someone goin low 9`s n/a w/a cast crank..............

Posted By: mopar dave

Re: what can be done to a 360 for strength - 12/13/13 06:59 PM

haven't heard that before. I thought head studs created a better clamping force to help prevent head gasket blow out? i'm currently using the ARP head bolts. guess I could reuse these and save alittle.

Posted By: dizuster

Re: what can be done to a 360 for strength - 12/13/13 07:04 PM

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Use ARP or stock head bolts. Use head studs and you will blow head gaskets.

I'd like to hear some logic behind that one. It flies in the face of common top engine builders best practices throughout the country.

Also, in my opinion a lot of the reason yours has lasted a long time is the fact that it's only got 28 degree's of timing in it.

Cylinder pressure early in the cycle puts an enormus stress on parts (and worse yet if it's detonating.) Remember if it's got a lot of cylinder pressure at TDC (or near it), it's trying harder to push the crank out the bottom of the block then it is trying to turn it!

Posted By: pittsburghracer

Re: what can be done to a 360 for strength - 12/13/13 07:07 PM

All I want to know is how long does it take to put 1800+ passes on an engine. Wholly crap.

Posted By: SSDart

Re: what can be done to a 360 for strength - 12/13/13 07:16 PM

Quote:

haven't heard that before. I thought head studs created a better clamping force to help prevent head gasket blow out? i'm currently using the ARP head bolts. guess I could reuse these and save alittle.

I have not seen this on a Mopar, but on a small block ford the studs will pull up the surface locally around the stud... went through this with a 302 once. The cure is a MLS gasket.......

I looked up 2 inch pin rods....... lot's available in the chevy listings..... but they are .927 pin.. not the cheapest route but more reliable........

Posted By: dartman366

Re: what can be done to a 360 for strength - 12/13/13 07:19 PM

Quote:

Quote:

Use ARP or stock head bolts. Use head studs and you will blow head gaskets.

I'd like to hear some logic behind that one. It flies in the face of common top engine builders best practices throughout the country.

Also, in my opinion a lot of the reason yours has lasted a long time is the fact that it's only got 28 degree's of timing in it.

Cylinder pressure early in the cycle puts an enormus stress on parts (and worse yet if it's detonating.) Remember if it's got a lot of cylinder pressure at TDC (or near it), it's trying harder to push the crank out the bottom of the block then it is trying to turn it!

bback when I was running the old 366 I would blow a head gasket once in a while using stock head bolts,switched over to ARP head bolts and problem went away, my opinion is the stock head bolts are too soft and will stretch too much under pressure, my opinion is use a good quality ARP head bolt at the very least on a cast iron head and head stud's on aluminim heads.

Posted By: mopar dave

Re: what can be done to a 360 for strength - 12/13/13 07:26 PM

i'll have to check prices on the 2" big end chevy rods and what it costs to turn the rod jounals down to that size. should lighten it up some using those rods.

Posted By: SSDart

Re: what can be done to a 360 for strength - 12/13/13 07:41 PM

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i'll have to check prices on the 2" big end chevy rods and what it costs to turn the rod jounals down to that size. should lighten it up some using those rods.

I have this combo now in my 360(Mine is the large chevy) my stuff is pretty damn light and you can get lighter I'm sure...... radiusing the sharp edges on the crank costs just a little time and makes the crank stronger....

Posted By: pittsburghracer

Re: what can be done to a 360 for strength - 12/13/13 07:54 PM

Just my oppionion but if you are only looking to run high 9's or 10's you are really over-thinking things. 10.50's at 3300 pounds is a cake walk in these wonderful times.

Posted By: mopar dave

Re: what can be done to a 360 for strength - 12/13/13 08:04 PM

best this past season was a 10.35 with current combo. just lookin to break into 9's and not wanting to just throw something together with higher compression and hope it does it. want to build it right and make it last awhile.

Posted By: deaks

Re: what can be done to a 360 for strength - 12/14/13 01:32 AM

If you have run 131, you should be going very low 10's, what are your 60 ft times ?
Mick

Posted By: dizuster

Re: what can be done to a 360 for strength - 12/14/13 01:45 AM

Not true at all... it just depends on how the car is on the bottom end. My turbo car is an extreme case, but it's only been 10.08@136 (stock 360 block 1/2 fill, stock cast crank BTW.)

Posted By: qwkmopardan

Re: what can be done to a 360 for strength - 12/14/13 04:10 AM

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All I want to know is how long does it take to put 1800+ passes on an engine. Wholly crap.

If I raced that car full time, I also have the 89 LeBaron, it would only take a little over 4 seasons. That eng. was first used in 2007, and full time the first 2 years and then I got the LeBaron running.

Posted By: cudaman1969

Re: what can be done to a 360 for strength - 12/14/13 04:20 AM

I have been reading the posts on here and I'm impressed with the times and power of the 360. I put together a 360-380hp to put in my 69 notch and thought maybe 12.00. Should I be prepared to go faster?Engine been worked quite a bit

Posted By: qwkmopardan

Re: what can be done to a 360 for strength - 12/14/13 04:40 AM

Quote:

Quote:

Use ARP or stock head bolts. Use head studs and you will blow head gaskets.

I'd like to hear some logic behind that one. It flies in the face of common top engine builders best practices throughout the country.

The studs at full 1/2" dia. do not stretch enough at 100ft. lbs. of torque. The stock head bolts as well as the ARP head bolts have the dia. reduced to 7/16" from about 1/4" below the head to just above where the threads start, which allows for more stretch at 100ft.lbs. Main studs work great because there is nothing between the two surfaces being clamped, unlike between the block and the head. More stretch on a head bolt allows more load to stay on when the gasket further compresses form heat cycling. If you try torqueing more than 100 ft. lbs., to, say, 135 ft. lbs., which would further stretch the stud, you will more than likely pull the threads out of the block.

I had studs on a 360 years ago and it would blow head gaskets at 10.75 to CR. So one day I happened to notice how the dia. on the bolts was not full size, so I turned the ARP studs to 7/16" between the threads and never blew another head gasket on that eng. and I ran it for a couple more years until it broke the stock cast 360 crank into 3 pieces.

Posted By: Crizila

Re: what can be done to a 360 for strength - 12/14/13 04:59 AM

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is there anything that can be done to a 1971 360 block that would make it alittle stronger? the block has a short fill and uses arp main studs with stock caps. are there any girdles out there that work? what about aluminum main caps to absorb some stress? will be a 13.5:1 7000rpm street/strip deal. maybe 15 passes/yr for a couple years, than I will be moving on to big block.

1/2 fill, Milodon 4 blt mains, studs, Scat crank / H beams. Icons.

Attached picture 7958150-rotatingassembly.jpg

Posted By: qwkmopardan

Re: what can be done to a 360 for strength - 12/14/13 05:06 AM

If you turn the crank .025 under you use a large jrnl sm. chevy rod. The 2" journal are not much lighter. Either way the sides will have to be opened .010 on each side of the jrnl., or the rods will have to narrowed up by .010 off the non chamfered side. Generally you don't go to the 2" jrnl. until you have to, because of larger stroke which requires too large a notch in bottom of cyl., usually over 4.125 stroke on a sm. mopar.

I use RPM brand I-Beam rods, either 6.125 or 6.250 and they can be bought for the $400 price range. They are right at 600 grams, compared to eagle or scat h-beams at 700 grams. I have 6.250 RPM rods in the Demon.

Posted By: pittsburghracer

Re: what can be done to a 360 for strength - 12/14/13 05:17 AM

I would get shot or hung for letting this one out of the bag but most of the involved party is dead and gone or about out of the game. A close Friend worked for one of the really big Ford teams and they were taught to flip a head over and chamfer the head bolt holes on the deck surface of the head. They found out that as the head was being torqued down it was pulling the head harder under the head bolts and distorting the head mating surface. Putting a chamfer on the head bolt hole spread the pressure evenly across the deck.

Posted By: mopar dave

Re: what can be done to a 360 for strength - 12/14/13 06:38 AM

the Molnar H beam in a 6.250 length with standard Chevy pin weights 512g with 3/8 arp2000 bolts. can I use the 3/8 bolts in this combo or should I be using the 7/16 bolt. looks like the bigger bolt adds a lot of weight. pistons will be between 400-450G.

Posted By: pittsburghracer

Re: what can be done to a 360 for strength - 12/14/13 07:03 AM

I would go with the 7/16 rod bolts. Not a good place to shave weight.

Posted By: skrews

Re: what can be done to a 360 for strength - 12/14/13 08:01 AM

Quote:

I would get shot or hung for letting this one out of the bag but most of the involved party is dead and gone or about out of the game. A close Friend worked for one of the really big Ford teams and they were taught to flip a head over and chamfer the head bolt holes on the deck surface of the head. They found out that as the head was being torqued down it was pulling the head harder under the head bolts and distorting the head mating surface. Putting a chamfer on the head bolt hole spread the pressure evenly across the deck.

The other part to this is to chamfer the head bolt holes in the block a bit.

Posted By: pittsburghracer

Re: what can be done to a 360 for strength - 12/14/13 08:09 AM

Quote:

Quote:

I would get shot or hung for letting this one out of the bag but most of the involved party is dead and gone or about out of the game. A close Friend worked for one of the really big Ford teams and they were taught to flip a head over and chamfer the head bolt holes on the deck surface of the head. They found out that as the head was being torqued down it was pulling the head harder under the head bolts and distorting the head mating surface. Putting a chamfer on the head bolt hole spread the pressure evenly across the deck.

The other part to this is to chamfer the head bolt holes in the block a bit.

Shhhhhhhhh.

Posted By: SSDart

Re: what can be done to a 360 for strength - 12/14/13 11:52 AM

Quote:

the Molnar H beam in a 6.250 length with standard Chevy pin weights 512g with 3/8 arp2000 bolts. can I use the 3/8 bolts in this combo or should I be using the 7/16 bolt. looks like the bigger bolt adds a lot of weight. pistons will be between 400-450G.

If you go to a Mopar spec piston, then you won't have to use that long rod....

Posted By: B3422W5

Re: what can be done to a 360 for strength - 12/14/13 03:19 PM

Quote:

Quote:

the Molnar H beam in a 6.250 length with standard Chevy pin weights 512g with 3/8 arp2000 bolts. can I use the 3/8 bolts in this combo or should I be using the 7/16 bolt. looks like the bigger bolt adds a lot of weight. pistons will be between 400-450G.

If you go to a Mopar spec piston, then you won't have to use that long rod....

Lot of people like/ prefer the long rod with 4 inch crank. I used 6.300 Compstar rods which worked extremely well.

Posted By: mopar dave

Re: what can be done to a 360 for strength - 12/14/13 04:56 PM

I would like to use a short CH piston to get it real lite. I really want to science this build out as it will be my last go fast build and chance to break into the 9's. the next one after that will be a bb stroker just for cruising and to show. gonna get away from chasing numbers and sell my trailer as well. anyway I really want to get this sb right this time around.

Posted By: clonestocker

Re: what can be done to a 360 for strength - 12/14/13 05:15 PM

How heavy is your car?

Posted By: mopar dave

Re: what can be done to a 360 for strength - 12/14/13 05:18 PM

3300 with me. the best 60 was a 1.45

Posted By: mshred

Re: what can be done to a 360 for strength - 12/14/13 05:21 PM

Quote:

I would like to use a short CH piston to get it real lite. I really want to science this build out as it will be my last go fast build and chance to break into the 9's. the next one after that will be a bb stroker just for cruising and to show. gonna get away from chasing numbers and sell my trailer as well. anyway I really want to get this sb right this time around.

, I would sell what you have, build a BB pump gas stroker that will be able to cruise around and run 9's

...I don't see the point in spending all the money twice on the SB when you are going to go BB in the end and be able to reach your goals

Posted By: mopar dave

Re: what can be done to a 360 for strength - 12/14/13 05:34 PM

those bb strokers like the 470, 499 have to be built stout to run 9's. if my bb runs 10's and I can drive it anywhere with low maintenance using a hydro roller easy on springs i'll be extremely happy.

Posted By: barracuda man

Re: what can be done to a 360 for strength - 12/14/13 05:44 PM

Quote:

I would get shot or hung for letting this one out of the bag but most of the involved party is dead and gone or about out of the game. A close Friend worked for one of the really big Ford teams and they were taught to flip a head over and chamfer the head bolt holes on the deck surface of the head. They found out that as the head was being torqued down it was pulling the head harder under the head bolts and distorting the head mating surface. Putting a chamfer on the head bolt hole spread the pressure evenly across the deck.

How about a picture of this process.Could one use a counter sink to do this.Sounds interesting.

Posted By: pittsburghracer

Re: what can be done to a 360 for strength - 12/14/13 06:40 PM

I'm sorry but I have no pictures at this time. I always did mine by hand with a carbide burr but that's just me. I would try it first on a piece of scrap metal to get some practice. Remember its not a big crazy chamfer. For example on a small block head ( 1/2 inch bolt ) its only gonna be like 3/16 - 1/4 inch max 45 degree chamfer. Just enough to spread the pressure from directly under the bolt head.

Posted By: Thumperdart

Re: what can be done to a 360 for strength - 12/14/13 07:07 PM

Quote:

Quote:

I would like to use a short CH piston to get it real lite. I really want to science this build out as it will be my last go fast build and chance to break into the 9's. the next one after that will be a bb stroker just for cruising and to show. gonna get away from chasing numbers and sell my trailer as well. anyway I really want to get this sb right this time around.

My , I would sell what you have, build a BB pump gas stroker that will be able to cruise around and run 9's ...I don't see the point in spending all the money twice on the SB when you are going to go BB in the end and be able to reach your goals

Doin that right now..................

Posted By: Thumperdart

Re: what can be done to a 360 for strength - 12/14/13 07:10 PM

Quote:

those bb strokers like the 470, 499 have to be built stout to run 9's. if my bb runs 10's and I can drive it anywhere with low maintenance using a hydro roller easy on springs i'll be extremely happy.

Nothing fancy or stout here..........stock crank, 13 year old Eagle rods and JE pistons, home ported rpm`s w/stock window,.680-.660 Isky solid roller, Victor intake and an old hp-1050 dommy............

Posted By: mopar dave

Re: what can be done to a 360 for strength - 12/14/13 07:12 PM

do you think you could make a 700 mile round trip without any issues?

Posted By: SSDart

Re: what can be done to a 360 for strength - 12/14/13 07:18 PM

Quote:

I would like to use a short CH piston to get it real lite. I really want to science this build out as it will be my last go fast build and chance to break into the 9's. the next one after that will be a bb stroker just for cruising and to show. gonna get away from chasing numbers and sell my trailer as well. anyway I really want to get this sb right this time around.

I would not worry so much about the CH...... The area in the skirt does not add too much wt with the pistons available these days....... going to a narrow pin also reduces wt....... the longer rod will kill off power...

Posted By: Thumperdart

Re: what can be done to a 360 for strength - 12/14/13 07:30 PM

Quote:

do you think you could make a 700 mile round trip without any issues?

Don`t see why not but havn`t even considered that honestly. I`ve driven about 90 minutes at a time and cruise the freeway from time to time thankxxx to a mild lobed Isky solid roller and a good cooling system.

Posted By: B3422W5

Re: what can be done to a 360 for strength - 12/14/13 10:23 PM

Disagree about a long rod killing off power, that isn't true at all.
In fact the guy who owns my old car has been 9.62 at 140 with it at 3200 pounds on super stock springs and 28by 10 DOT tires. That is with off the shelf headers and a 727 trans.
Don't know of many, if any, similar W5/ Indy combo's that run any better.

To the OP, we're it me I would mill the heads if you have flat tops to raise compression, run a cam to match the compression, and swap the 727 you have already for a 904 .
The tranny swap should be good for 1.5 tenths, and a little more cam and compression will knock another 2 or 3 tenths out of it easily.
I would be willing to bet another another point in compression( to 12.5 compression) the correct cam, and the 904 would get the car into the 9's.
This all assumes the heads are good.
If anything those heads have a bit more potential than W5 head, which has smaller valves and less cross section.
Doesn't take anything special to get an A body in the 9's with a roller and Indy heads

Posted By: Thumperdart

Re: what can be done to a 360 for strength - 12/15/13 01:08 AM

Quote:

Disagree about a long rod killing off power, that isn't true at all.
In fact the guy who owns my old car has been 9.62 at 140 with it at 3200 pounds on super stock springs and 28by 10 DOT tires. That is with off the shelf headers and a 727 trans.
Don't know of many, if any, similar W5/ Indy combo's that run any better.

To the OP, we're it me I would mill the heads if you have flat tops to raise compression, run a cam to match the compression, and swap the 727 you have already for a 904 .
The tranny swap should be good for 1.5 tenths, and a little more cam and compression will knock another 2 or 3 tenths out of it easily.
I would be willing to bet another another point in compression( to 12.5 compression) the correct cam, and the 904 would get the car into the 9's.
This all assumes the heads are good.
If anything those heads have a bit more potential than W5 head, which has smaller valves and less cross section.
Doesn't take anything special to get an A body in the 9's with a roller and Indy heads

Good running combo 4 sure..............

Can that car be driven the said 700 miles round trip?

Posted By: B3422W5

Re: what can be done to a 360 for strength - 12/15/13 04:08 AM

Quote:

Quote:

Disagree about a long rod killing off power, that isn't true at all.
In fact the guy who owns my old car has been 9.62 at 140 with it at 3200 pounds on super stock springs and 28by 10 DOT tires. That is with off the shelf headers and a 727 trans.
Don't know of many, if any, similar W5/ Indy combo's that run any better.

To the OP, we're it me I would mill the heads if you have flat tops to raise compression, run a cam to match the compression, and swap the 727 you have already for a 904 .
The tranny swap should be good for 1.5 tenths, and a little more cam and compression will knock another 2 or 3 tenths out of it easily.
I would be willing to bet another another point in compression( to 12.5 compression) the correct cam, and the 904 would get the car into the 9's.
This all assumes the heads are good.
If anything those heads have a bit more potential than W5 head, which has smaller valves and less cross section.
Doesn't take anything special to get an A body in the 9's with a roller and Indy heads

Good running combo 4 sure.............. Can that car be driven the said 700 miles round trip?

Lol..... No..... The cam in it now is a spring eater..... The milder one I ran I drove around on the street some, but I only ran the numbers in my signature.....

Posted By: SSDart

Re: what can be done to a 360 for strength - 12/15/13 01:12 PM

Quote:

Disagree about a long rod killing off power, that isn't true at all.
In fact the guy who owns my old car has been 9.62 at 140 with it at 3200 pounds on super stock springs and 28by 10 DOT tires. That is with off the shelf headers and a 727 trans.
Don't know of many, if any, similar W5/ Indy combo's that run any better.

When I originally joined in on this thread, I thought the OP was building a stock stroke 360......... The long rod would be brutal in that...

Posted By: mopar dave

Re: what can be done to a 360 for strength - 12/15/13 04:14 PM

Sorry if i wasnt clear. 360 block 4" stroke.

what can be done to a 360 for strength