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Discussion Starter · #1 ·
Anyone know the limitations of a stock 351W roller truck block with 2 bolt mains? Max RPMs?

I know it was popular to take roller 351W blocks, slap a pair of 4V Cleveland heads on them and rev them to the moon, I just dont know how long it’ll last.
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A lot of the limit depends on how well it's machined, assembled, set up and tuned. I've read they are good for 700-800hp. My brother has a 418W in an '88 Ranger. It see's 7000+ regularly. Like every single time he drives it. He's gone 123mph plus and roached a built C4, then wounded the more fortified trans, twisted 2 sets of axles now, smoked a detroit locker, and twisted the out put yoke. Engine has been fine save for the first trans failure that drove the crack forward and wiped out the trust resulting in a rebuild.

The big 3" main journals are said to be less than desirable, but there are an awful awful lot of stock block 351W based engines terrorizing the streets and strips of North America.
 

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'90 Windveil Blue LX (Dart Turbo T56)
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Anyone know the limitations of a stock 351W roller truck block with 2 bolt mains? Max RPMs?

I know it was popular to take roller 351W blocks, slap a pair of 4V Cleveland heads on them and rev them to the moon, I just dont know how long it’ll last.
there are two approaches...

#1 take a gamble and hope that it lasts

#2 get it done right the first time around, which will be more costly up front but cheaper in the long run

short term pain and long term gain

i originally went with a '69 block and spend some $$$ on machine work, balance, custom pistons and initially all was good but then it split at low 700s to the tire (6000rpm shift point), and now i'm running a dart iron eagle and wish i did it that way from day one... live and learn.
i think in my case it was the stock cast crank that did me in as there was lot of cap walk even with arp studs, but then again who truly knows if a forged crank would have made a difference.
 

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Discussion Starter · #4 ·
there are two approaches...

#1 take a gamble and hope that it lasts

#2 get it done right the first time around, which will be more costly up front but cheaper in the long run

short term pain and long term gain

i originally went with a '69 block and spend some $$$ on machine work, balance, custom pistons and initially all was good but then it split at low 700s to the tire (6000rpm shift point), and now i'm running a dart iron eagle and wish i did it that way from day one... live and learn.
i think in my case it was the stock cast crank that did me in as there was lot of cap walk even with arp studs, but then again who truly knows if a forged crank would have made a difference.
Im considering a 408 with forged internals with 4V heads but I dont want to blow it up in a year of racing it. Hearing that though, the 351W Boss Block is sounding more appealing.
 

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'90 Windveil Blue LX (Dart Turbo T56)
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have you seen this beast with the ausi heads and intake

 
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1989 GT
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Im considering a 408 with forged internals with 4V heads but I dont want to blow it up in a year of racing it. Hearing that though, the 351W Boss Block is sounding more appealing.
I’m in the middle of my new build using stock block 414 with all forged rotating assembly and main studs.
Long ass story how I had to sort out the motor but if I was doing it again I’d just have gone dart block.

Im going to have to detune my motor as the supercharging going on it would be good for 20 lbs of boost. I’m likely going to be using only 10-12 lbs of boost so I don’t split the block.
 

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92 Mustang LX
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I agree with tjm73.
I know many friends who have/had 408s and 427s, stock 2 bolt truck blocks, good machining, balancing & bottom end support, H/C/I making 600+ hp and 7000 rpm racing season after season with only minor freshening here and there.

I also know a couple local people that used stock ”older year” 2 bolt’s with C3 Yates heads making around 700+ turning 7500 rpm with no problems either.

It all depends on related components and whether it’s N/A or with boost, but from what I’ve seen 700hp-7000rpm safely w/proper bottom end support and internals.

Everyone I know that used them upgraded to better stuff before they got a chance to break one.
 
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Discussion Starter · #9 ·
There was a guy on the turbo forum ran 8.90 at 155 with a stock short block. He bent the rods in it after 250-300 passes.
The rods isnt the first thing I would ever expect to get “bent” in a stock short block turbo car, maybe they weren’t aftermarket? Or just cheap OEM replacements. No forged EAGLE/Scat rods are bending…
 

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have you seen this beast with the ausi heads and intake

That is a 100% effort piece. Not the average build.

Changing things up for 2022 with an iron block and a 60mm camshaft.
 

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i run a forged 408 stock block. 10:1, e50-e85, v3 si, 8" crank 3" upper. i limit rpms to 5000-5200. also 3.08 ring gear.

point is, bad machining, bad tune, too high an rpm will take its toll on a stock block.
 

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The rods isnt the first thing I would ever expect to get “bent” in a stock short block turbo car, maybe they weren’t aftermarket? Or just cheap OEM replacements. No forged EAGLE/Scat rods are bending…
Yes untouched salvage yard 92 van motor. Ran 10.90 stock long block. Ran 9.50 with a 500 lift cam and gt40p heads. Then tfs 170 heads and 560 lift cam to get to 8.90.

I also saw in another thread. The block can crack in the motor mount area when going faster than 1.3 60ft times.

You asked for limits.
 

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Yes untouched salvage yard 92 van motor. Ran 10.90 stock long block. Ran 9.50 with a 500 lift cam and gt40p heads. Then tfs 170 heads and 560 lift cam to get to 8.90.

I also saw in another thread. The block can crack in the motor mount area when going faster than 1.3 60ft times.

You asked for limits.
carburated?
 

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have you seen this beast with the ausi heads and intake

love that build,ive always wandered why arent more people using cleveland style heads, john kaase says canted valve heads can make a big diference as they are more centered towards the middle of the cylinder
 

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love that build,ive always wandered why arent more people using cleveland style heads, john kaase says canted valve heads can make a big diference as they are more centered towards the middle of the cylinder
Because 99% of the customer market is comprised of power adders and 400-600hp naturally aspirated builds and the added costs and headaches for the avg hobbyist diminish the cleveland head almost entirely. When you can take a 240 hi port, super vic and a big turbo on a 427 and run 4.60s, thats why.
 

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Because 99% of the customer market is comprised of power adders and 400-600hp naturally aspirated builds and the added costs and headaches for the avg hobbyist diminish the cleveland head almost entirely. When you can take a 240 hi port, super vic and a big turbo on a 427 and run 4.60s, thats why.
makes sense,they still are some awsome heads and its cool that there are companies making them better than ever
 
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