I know there are some very fast and experienced racers on this board.
What are some of the top things that I can do to a 76' small block 360 to make it more durable without breaking the bank.
Because the bank is already broke with the purchase of below parts: new heads ($2200) New 78mm turbo and parts ($840) New sniper EFI ($1250) Machining and balance ($??)
I've acquired parts to make more HP than I think the stock block may be able to handle. Not sure, never been there or done that. Yet. Goal is 700 or more blown/turboed. Both if need be.
I do have diamond forged pistons 1/16,1/16 rings Main studs Eagle SIR I beam rods (says good to 500hp??) I will NOT be spinning this thing above 6000 rpms
Someone mentioned a short fill. Someone else said I need a forged crank. What about a main girdle?
For those of you who have done it not just hypothesized about it. What's the STRAIGHT scoop?
Last edited by prochargedmopar; 06/17/1711:29 AM.
"Old" member Registered: Sep 2001 Lost my credentials, I'm Back!! LOL 71 Ply Satellite Procharged 73 Dodge Dart Swinger 73 Ford F-100 390/Sniper efi/back to carb 01 Town and Country Limited 08 Dodge 2500 6.7 5" Deleted 02 Mercedes C230K 19 Camry
Re: 70's small block durability mods for 700hp
[Re: Prochargedmopar]
#2322534 06/17/1709:36 AM06/17/1709:36 AM
We finally hurt an engine (408) last year and something hit the block so I'm assuming a rod broke but it's not apart yet for me to see. This was a K1crank and K1 rods with upgraded bolts which I always do. It was rebuilt 3 times and in need of its 4th when my son asked to borrow it and finally let go. I particularly blame running alcohol as it's harder on bearing, bore wear, and other issues.
Do you want to trust imported rod bolts? ARP makes several different quality and priced rod bolts, all in 7/16 diameter The #8740 are the cheapest and weakest , their ARP 2000 are better and more expensive and their L19 bolts are the most expensive and strongest for all racing applications with a lot(500+ HP and 7000+ RPM) The piston total weight and ring pack affect drag and weight, and the RPM they (all components)will fail at Good luck, buy the best rods, pistons, rings and bearings you can for this build, not the cheapest
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: 70's small block durability mods for 700hp
[Re: Prochargedmopar]
#2322709 06/17/1706:31 PM06/17/1706:31 PM
Do you want to trust imported rod bolts? ARP makes several different quality and priced rod bolts, all in 7/16 diameter The #8740 are the cheapest and weakest , their ARP 2000 are better and more expensive and their L19 bolts are the most expensive and strongest for all racing applications with a lot(500+ HP and 7000+ RPM) The piston total weight and ring pack affect drag and weight, and the RPM they (all components)will fail at Good luck, buy the best rods, pistons, rings and bearings you can for this build, not the cheapest
Current bob weight is calculated at 1932. I used mopar rod bolts in stock rods for 72k miles without issue. 5800 rpm redline and 10psi. RPM will not be over 6k, most likely 5500 so I could use STOCK rod bolts and never have a problem.
Compression strength around the base of the big end on the rod beam is what I need. Nothing is going to fly apart in this engine. Gonna get smashed or twisted from boost first. . :-)
Last edited by prochargedmopar; 06/17/1706:39 PM.
"Old" member Registered: Sep 2001 Lost my credentials, I'm Back!! LOL 71 Ply Satellite Procharged 73 Dodge Dart Swinger 73 Ford F-100 390/Sniper efi/back to carb 01 Town and Country Limited 08 Dodge 2500 6.7 5" Deleted 02 Mercedes C230K 19 Camry
Re: 70's small block durability mods for 700hp
[Re: Prochargedmopar]
#2322715 06/17/1706:42 PM06/17/1706:42 PM
Its a junkyard base yes but it has been taken apart, the rings have been gapped, the cam has been changed, fastners changed etc. Matts truck is impressive on the dyno for sure and its no slouch on the track but it doesn't spend much time there.
68 Barracuda Formula S 340
Re: 70's small block durability mods for 700hp
[Re: Bad340fish]
#2322995 06/18/1711:59 AM06/18/1711:59 AM
Its a junkyard base yes but it has been taken apart, the rings have been gapped, the cam has been changed, fastners changed etc. Matts truck is impressive on the dyno for sure and its no slouch on the track but it doesn't spend much time there.
All fasteners and gaskets in his engine are reused against factory recommendations. Even the "stretchy" head bolts. Everything is torqued to 65ish lb. ft. or untill it FEELS like it is about to snap.
Like I said.
Unfare advantage as chevy built this engine using racing technology. 6 bolt skirted block. Cylinder bores special hardened material that does not get a ridge even after 250k miles. Crank good to 1000hp reliably. 2nd gen rods good to 900hp. Heads super high angle factory cast ports with excellent deck thickness. Shorty ductile Iron headers. Solid pistons and intake manifold.
Blah. (sticks finger down throat)
"Old" member Registered: Sep 2001 Lost my credentials, I'm Back!! LOL 71 Ply Satellite Procharged 73 Dodge Dart Swinger 73 Ford F-100 390/Sniper efi/back to carb 01 Town and Country Limited 08 Dodge 2500 6.7 5" Deleted 02 Mercedes C230K 19 Camry
Re: 70's small block durability mods for 700hp
[Re: Prochargedmopar]
#2323133 06/18/1704:10 PM06/18/1704:10 PM
Definitely do a forged crank, ditch the I beams and get some H beams, Also I would suggest doing the oil cross over line in the lifter valley, tap in-between 8 and 6 lifter valley and 1 and 3 lifter valley, connect them with a I believe 3/8 tubing, have done it on last two motors and it works great, oil doesn't have to travel down the passenger side to the front main up to the drivers side and back, puts oil directly on drivers side and helps aid in oiling to front main bearing, there is actually a really good article on oiling mods somewhere online, I did all I could, drilling out main passages to true 1/2'' and mains from the lifter feed to true 9/32, I was really surprised how small they got once you got 2 inches in, I always run full grove main bearings as well, the way I see it with full grove bearings your rods get oiling all the time, with 1/2 or 3/4 bearings you are restricting oil to rods to timed oil, just like the rocker arms, just a few tricks that could help it live at that power...
Re: 70's small block durability mods for 700hp
[Re: 10sec.dart]
#2323640 06/19/1703:25 PM06/19/1703:25 PM
The 360 has the largest main bearings of Chrysler OEM V8s. I'd not put $$$ into a forged crank, buy instead a new 9000 Series from SCAT. Also the SIR rods have been good for the last 4 years or so but I'd replace them with SCAT Pro series. There is no inherent superiority of H-beam over I-beam, and horsepower ratings for connecting rods are bogus from the start. Having said that, the SCAT have several good points, material, 7/16" bolt size, and low weight especially compared to the stock rods.
By keeping rpm low, you are extending the life of the engine.
R.
Last edited by dogdays; 06/19/1703:43 PM.
Re: 70's small block durability mods for 700hp
[Re: Prochargedmopar]
#2323679 06/19/1704:41 PM06/19/1704:41 PM
First of all I have to say, depending on a used stock crank at 700hp is foolish.
Now how's it going to add up? 9.600 block, 3.58 stroke, 6.125 rods means the pistons have to be about 1.685 compression height. You said "Must be 1.123-1.125 length" which I don't understand. 4" bore pistons with a chevy pin size and 1.685 compression distance are not falling out of any trees. They're custom
a 350 chevy with 3.75 stroke and 6.000 rods needs a piston with compression height of 1.12, is that where that number came from?
Anyway, I agree with Cab that trimming the rods' big ends sounds like the right way to go.
The block can use every trick you can give it. Girdle, short fill, etc.