stock bottom end.

Figment

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I want to know if my '76 440 would stand up to about 6lbs. boost from a pair of garret turbo's that came from a couple of 3.8L Gm engines? I know the compression is down around 8.5 on the 440 and without tearing it apart it runs fine, meaning no blue or white smoke what so ever. I'm in the process of finding my compression gauge and doing a compression test anyway although I'll pull the heads off to change the head gaskets, and put a new timing chain in, for extra insurance if the bottom end will hold up.

I'm already getting plans in the works and gathering the parts to get my 727 rebuilt, and my 9.25 overhauled and a sure grip installed.

I like the tall gears in my NYer but I feel the 440 could use a little more help to step up in traffic, and the occasional 1/4 mile run just because so my cousins 5000lbs half ton with a 350 won't kick my *** so bad..
 
Do it and have a blast with it until it breaks something. Only worry about it IF it happens.
 
In my unprofessional opinion, probably not. Starting around 1975 Mopar switched from forged cranks to cast in the 440. The connecting rods are also a lighter duty piece. While reliable for normal street use, they are only good for up to 500hp. The extra pressure and HP from twin turbos would, in my opinion, likely prove to be too much for a stock 76 bottom end. If it were me putting on turbos, I'd be worried about scattering my cast internals on the asphalt trying to keep up with that 350.

That being said, I did find this...

"The extent of the engine preparation will depend entirely on how the engine is to be used. A supercharger can be installed on a stock engine with cast pistons and a cast crank as long as moderate boost (below 8 lbs.) is maintained and any detonation is strictly controlled. Engine speed should also be limited to 5,000 rpm. Detonation on cast pistons can easily break ring lands. Too much boost and/or detonation on a stock or worn engine can cause piston damage or burned valves. Most late model "smog" engines work well with a supercharger due to their lower compression ratios and smaller cam profiles."

How much boost are you thinking of running?
 
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Big Blue: Don't short sell the cast crank. Way too many disparaging remarks have been made about them by people using misconception rather than fact.
That crank, with new bearings installed exactly by the book, is more than good enough for that engine with a puffer on the street. If that crank breaks, it will because of other things. Example: Going 6000 rpm without a top-notch oiling system. That will croak a forged crank.
 
Commando, you pretty much summed up the post I quoted. Fine for the street with moderate boost and limited RPM. Personally I just wouldn't be comfortable going over much over 500 ponies on a cast crank or bolting on 150hp on a motor with 35yrs of wear and tear and cast parts, especially so without extensive knowlegde on running boost.

Most of my uncomfortability comes from seeing first hand how power adders can lead to detonation and broken ring lands, leading to starting over from square 1...
23652_1369369667429_1027340907_1112686_6738545_n.jpg

I didn't do the damage, but my father and I fixed it. NOS. And all the bearings were toast on a factory crate engine.

But then what do I know. It his money and motor. More than one person has built 500+ motors with cast cranks and they survived. They key is they built the motors for 500+ hp.
 
Bingo!
They BUILT the motor for 500+ hp.
Putting twin turbos on that old motor WILL break something. Probably a rod or whatever before the crank gives up. But whatever does pop, the crank may get caught in the collateral damage.
Actually I'm of two minds on this 440 twin-turbo thing.
1. If you don't
care, throw them on as is and wait for it to break, which it will, but you'll have had your fun with it on the cheap, or...
2. If you want to do it right, you gotta build the motor bottom up.
We're both in agreement that whatever way is chosen, you're going to get what you pay for.

BTW, I'm betting trying to adapt twin turbos from GM onto a 440 is going to be abandoned midway through because of too many hurdles that have to be overcome.
Seen it done many times but it wasn't just a plg 'n play deal.
 
I have seen a buick straight eight with two buick grand national turbos.
NOW THAT'S HOT RODDING.
Would love to have seen that.
That's the kind of really cool stuff you see over at The H.A.M.B.
 
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Well thanx for the info, but it isn't in the cards any more. The turbo's that I was looking at, are now scrap metal.

The reason why I was asking was that I don't have any experience with big blocks what so ever, even the grain trucks I've driven all have small blocks or strait 6's.

As for the hp I wouldn't get any where near there, I'd be happy with 400-450 hp., and there is no way I would let the stock rotating assembly go past 5000, not without rebuilding it, which I don't have the cash for. The 440 I do have has excellent oil pressure and compression, so it's good solid base for a street engine. New ignition system, carb, and few other goodies as time and money permit..

By the way commando, you must be the one selling the NY'er on Ebay. How come you never finished it? Talk about people starting projects and not seeing them through, and you seem to have the time and the money how come you don't go on the power tour and show them how to pro tour.
 
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You flatter me by thinking I've got the money!
And don't have the time because I'm my wife's caregiver.
And the 4 spd isn't finished, not "wasn't finished". And why it's for sale was in the ad: need the money.
Your 6 cyl. grain wagon would fit right in on The Tour, though.
 
You flatter me by thinking I've got the money!
And don't have the time because I'm my wife's caregiver.
And the 4 spd isn't finished, not "wasn't finished". And why it's for sale was in the ad: need the money.
Your 6 cyl. grain wagon would fit right in on The Tour, though.

Don't you be sassing me, boy, or I'll hand you your azz on a platter.
 
I don't know what all you have done to you 440, but I know that removing all the vacuum operated stuff under the hood helped my performance immensly on my stock 78 440. 33 yr old vacuum hoses can be a bad thing.

If you don't want/can't afford a complete rebuild I would call Hughes Engines, Comp cams, and lunati. The whiplash cam is designed to make maximum HP with stock parts, although you will need new valve springs and timing chain/gear set. The same would be true for any good RV cam whether it be Comp XE or Lunati Voodoo, just don't over cam your smogger. I think you would be very happy with a cam, dual plane intake with 750-850 carb, and dual exhaust combo.

As to the Buick with twi turbos this is the best picture I could find from 10 yrs ago.
7-5-201182647AM.jpg
 
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You flatter me by thinking I've got the money!
And don't have the time because I'm my wife's caregiver.
And the 4 spd isn't finished, not "wasn't finished". And why it's for sale was in the ad: need the money.
Your 6 cyl. grain wagon would fit right in on The Tour, though.

Don't you be sassing me, boy, or I'll hand you your azz on a platter.

1.I'm not rich either, hell I only paid $600 bucks for my NY'er and still making payments.
2. I'm big enough to say I don't know, I never grew up with Mopar big blocks around, so my knowledge is zip. You were coming off rather brash almost like you were daring me to crank up the boost and scatter this engine. I'm simply asked for some info from the infinite knowledge that others possess.
3. As for my azz, I'm big enough to burn diesel and smart enough to respect my elders and also sass them when they need to be. Also my '69 6 cyl. C60 grain wagon now has a 300 hp Detroit 2 stroke diesel under the hood with a 6 speed allison automatic, hell it even got upgraded to disc brakes al the way around, so you could say it's a hot rod.
I don't know what all you have done to you 440, but I know that removing all the vacuum operated stuff under the hood helped my performance immensely on my stock '78 440. 33 yr old vacuum hoses can be a bad thing.

If you don't want/can't afford a complete rebuild I would call Hughes Engines, Comp cams, and lunati. The whiplash cam is designed to make maximum HP with stock parts, although you will need new valve springs and timing chain/gear set. The same would be true for any good RV cam whether it be Comp XE or Lunati Voodoo, just don't over cam your smogger. I think you would be very happy with a cam, dual plane intake with 750-850 carb, and dual exhaust combo.

As to the Buick with twi turbos this is the best picture I could find from 10 yrs ago.
7-5-201182647AM.jpg

Thanx for the info on the vacuum lines, but I found out the original fuel hoses were leaking, and this plastic thermo-quad has a tendency to hold onto parts that are supposed to move inside, and the gasket's on are leaking badly. While I've got it apart I'll try figure out the vacuum system and make it work a little more efficient.
 
Thanx for the info on the vacuum lines, but I found out the original fuel hoses were leaking, and this plastic thermo-quad has a tendency to hold onto parts that are supposed to move inside, and the gasket's on are leaking badly. While I've got it apart I'll try figure out the vacuum system and make it work a little more efficient.


Yeah, mine gets much better fuel mileage since replacing a cracked section of fuel line coming off the tank. lol. Same problems with the thermobog. It is leaking from somewhere. Just gonna replace it and the cast intake with edelbrock pieces. Picked up a CH4B two days ago, now trying to offload a double pumper to fund an edelbrock.

I will tell you that after fixing my vacuum leaks and removing all the smog crap the difference was enough to make my father and best friend both blurt out, "Holy $h!t!"
 
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