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Old 07-18-2004, 04:26 PM   #1
OLDCOUNTRY01
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427 chev ???

Can someone tell me what the difference is in a 427 car engine and 427 out of a truck? What difference would there be in performance?
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Old 07-24-2004, 01:29 PM   #2
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Re: 427 chev ???

There are lots of 427 truck engines out there, so your question is a common one. Often, the pick-up trucks used automotive 427 engines. The 427 truck engines were used in the 2 to 5 ton big trucks.

The engines are quite different, and the truck engine is ABSOLUTELY USELESS for a performance application.
I cannot over emphasise this enough. Don't even consider it.

The truck engine has a 1 inch higher deck height, so the cast iron, small port truck manifold is the only one which will work. All the high preformance stuff wont fit.
The block is wider and taller, and will not fit well in most cars anyways.
The block has very tall, heavy, low compression, low revving pistons, which are the only ones that will fit.
Finally, there is no way to cut the block deck down so the automotive 427 parts will fit.
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Old 08-02-2004, 12:50 PM   #3
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Re: 427 chev ???

At the risk of opening a can of worms, I must disagree. The "high block" or "tall deck" is VERY popular among racers today. The 427 is a "big bore" version of the 366. They are bullet proof!
The only big block pickup engines I've seen have been either the 396, 402 or 454. I don't recall a light truck coming from the factory with a 427. That doesn't mean they never made one, just it must be rare.
The big advantage of the tall deck, is the ability to put much longer connecting rods in the engine, and use the good pistons available for the standard deck. Weiand makes spacer plates for both oval and rectangular port heads, allowing the use of standard deck intakes.
Tall deck blocks are ALL 4-bolt main. They ALL have forged steel cranks (3.76" stroke). They use the stock length rod (6.135") and the piston has an extra .400" added to the top, whcih allows the use of an extra compression ring (not uncommon in heavy duty applications).
Eagle and others, make a rod exactly .400" longer, making the swap easy. Even longer rods are more commonly used (6.7 and 6.8, respectively). We in the Pontiac world are grateful for this popularity, as it has significantly reduced the cost of good rods for the Pontiac. We use a ton of the 6.8 jobs. Adding to the rod length improves the rod/stroke ratio (not very good on stock BBs). it also reduces the rod angle, and allows for more "dwell" time (in degrees) at TDC and BDC. More time at TDC will give more cylinder pressure under firing, and it will fill better on the intake stroke, when it dwells at BDC.
The one negative (aside from sheer weight) is the exhaust. The headers will be up higher and further out with the tall deck...
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Old 08-07-2004, 11:58 AM   #4
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Re: Re: 427 chev ???

Quote:
Originally Posted by MrPbody
At the risk of opening a can of worms, I must disagree. The "high block" or "tall deck" is VERY popular among racers today. The 427 is a "big bore" version of the 366. They are bullet proof!
The only big block pickup engines I've seen have been either the 396, 402 or 454. I don't recall a light truck coming from the factory with a 427. That doesn't mean they never made one, just it must be rare.
The big advantage of the tall deck, is the ability to put much longer connecting rods in the engine, and use the good pistons available for the standard deck. Weiand makes spacer plates for both oval and rectangular port heads, allowing the use of standard deck intakes.
Tall deck blocks are ALL 4-bolt main. They ALL have forged steel cranks (3.76" stroke). They use the stock length rod (6.135") and the piston has an extra .400" added to the top, whcih allows the use of an extra compression ring (not uncommon in heavy duty applications).
Eagle and others, make a rod exactly .400" longer, making the swap easy. Even longer rods are more commonly used (6.7 and 6.8, respectively). We in the Pontiac world are grateful for this popularity, as it has significantly reduced the cost of good rods for the Pontiac. We use a ton of the 6.8 jobs. Adding to the rod length improves the rod/stroke ratio (not very good on stock BBs). it also reduces the rod angle, and allows for more "dwell" time (in degrees) at TDC and BDC. More time at TDC will give more cylinder pressure under firing, and it will fill better on the intake stroke, when it dwells at BDC.
The one negative (aside from sheer weight) is the exhaust. The headers will be up higher and further out with the tall deck...
Thank you for providing useful information. I did not know about the recent availability of those rods and spacers.

If the engines are 'popular among racers', do people prefer to build then for the street? I suspect the degree of work and money required to make a tall deck run well realistically put it out of consideration for a novice builder, when automotive BB's are available.
This person obviously wants no surprises, (or they would not have posted) so I would have throught a short deck BB is better, no?
Furthermore, the weight and clearance problems would make it a hassle for a street going automotive application (big hood bulge, I guess).
I am assuming this person is on a budget, like most of us and wants to get the most appropriate engine for a budget application.

(BTW I meant 454 pick up trucks, not 427)
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