427 tall deck?

[kornball426]

Hey guys, I'm thinking about buying this motor it's a 72 Chevy or GMC 427 truck motor. Anyone ever put one of these in a G-body? The motor needs a rebuild but it seems cheap 250 bucks complete... I remember reading some stuff like you can't put aftermarket intakes on the truck blocks unless you put some kind of spacers in or something, because the heads are further apart because of the extra inch of deck height, is that true? Is there any other weird things with these that maybe I should steer clear of this motor?

Can you use standard BBC pistons in them, or do they have a different compression height?

Basically if I get it, I just want to do a very basic rebuild with mild upgrades... Just a mild cam, an intake, and headers (edit: scratch that keep the manifolds, I forgot BBC headers are super expensive for G-bodys ), get the heads redone with the hardened valve seats and get a 3 or 5 angle job on them. Or go for some better newer but still standard GM heads with the hardened seats already installed if the truck heads suck. And do a quick home port clean up and bowl blend. Nothing fancy, I'd want it to run on regular gas so low compression, and it would be going in my DD so I don't mind keeping it down in the 5,000-5,500 max revs kind of range.

Does that sound doable on the cheap?

 

[maddog20_20]

I would pass on it even at 250 - as you stated no aftermarket performance parts will work and I have never like the idea of using "spacers" for anything performance. I see late model 454s all the time on craigslist for $200-500 and even paying more for the core you will come out ahead without having to try and make something work with the tall deck

 

[kornball426]

Bummer... So it being a four bolt with a forged crank standard, it's not worth messing with?

My main goal is cheap(ish)... Just overhaul nothing fancy. I've been looking for an Olds 350 or 455, or I'd even go 403 although that's not my first choice. But I can't find any local Olds motors for sale that aren't high dollar stuff, I'd like to stay olds powered because it is easier since the car is already olds powered. But I've been considering chevy's, small block is the obvious choice for low buck... But if I can find a cheap big block that's better in my book.

 

[RITTER]

427 tall deck truck engines are completely different than a Corvette 427 big block. The weigh like a half of ton fully dressed. Any performance parts for them would have to be completely custom made. They are very low horsepower engines as well.

 

[kornball426]

Well as far as the weight goes, I read the TD is only supposed to be about 60 lbs more than a regular BBC, and the heads can easily be swapped for a more HP oriented design they're exactly the same as other BBC except the port design.But reading online other sources said some similar stuff to you guys.

I found out you need a special rod to use standard BBC pistons, they're readily available but ain't cheap between 5 and 6 hundred bucks. And the crank needs to be rebalanced after wards to work with the much lighter pistons and long rods. Also, you can buy either A; a manifold for a TD which is pricey, or B; Jegs makes spacers for use with standard BBC manifolds which I didn't price out but I bet they're not cheap. With the use of spacers you must have your distributor base machined down I think about an 8th inch if you wish to retain a stock style distributor, or you can use one with an adjustable base and collar which is available from Mallory, I didn't price it but I bet it's 300+ bucks or more.

Still I think it would be a cool engine, to utilize the standard crank with standard BBC pistons you would use a 6.8 rod vs. standard BBC 6.135 rod and a stroke 3.75 instead of 4.0 imagine what a screamer that motor could be! The rod geometry is about equal to a 327 Chevy. I'm tempted to buy the motor and just store it for a project down the road. But like you guys were saying, it's definitely not a good choice as just a mild replacement motor. So I think I'll pass on it since I'm pretty broke and can't afford to be collecting stuff for "down the road" projects. :|

But just thought I'd share some other stuff I learned, interestingly enough (to me at least) the blocks are popular with guys looking for monster cubic inches because the addition of a 4.25 stroker crank which requires no modification to the block, with 6.535 rods (IIRC) and a .060 overbore results in a 496 with a rod stroke ratio better than a stock 454 (and much better than a 496 made from a 454) and about equal to a stock 350. Other strokers I think are achievable with 4.375 and 4.5 inch cranks in this block without a ton of modification (requires clearance the block for the crank obviously), but that's about the limit before having to go to an aftermarket block.

 

[TURNA]

Unless you are building an all out "race" engine stay away from that tall deck.

It is 250 buxx for a reason.....NO ONE WANTS IT!!!!!!