Let me start by saying I Know nothing about big blocks other than simple basics and I have never even seen a 427 in real life. I have owned one greasy 454 out of a 81 suburban and I sold it today. So, today I bought a 427 chevy motor, without looking at it first. ( price was tooooo good) I have a few questions. The guy I bought it from said he bought a 55 chevy gasser 10 years ago. He had watched the car run in the 12's earlier in the weekend. When they were unloading the car at his house, he noticed the motor making a light ticking noise. He pulled the motor out and took it apart. At our local machine shop he was told someone had run alcohol through it when they shouldn't have and the skirts were tapping the block. There is NO damage to the block at all and the machine shop said it looked to them that it should just be a matter of replacing the pistons and possibly rods. They checked the crank and the mains and said they were (10/10?) And the block is .030 over Someone has removed all burs and edges from inside the block and there is a grayish white hard substance in the water jackets about 1/3 of the way down in the block (filler?) he gave me these numbers over the phone. block is # 3904351 heads are # 3904392 crank is # 3879621 I tried to find out more about this motor tonight and all I can find is it is most likely a 1967 L-88. I asked my buddy Rusty about this guy and he had nothing but good things to say about him. Rusty told me this guy used to be THE guy to go to for hotrod stuff. I just met him tonight for the first time. But when he offered the motor I jumped on it more to call his bluff than anything. He stuck out his hand and said DEAL. My questions: Will this motor assuming it's not damaged, really make a 12s motor? He mentioned that it is called a "tall deck" motor but I can't find anything other than L-88 listing. Are L-88 all tall decks? Is this a truck motor or car motor? He also mentioned that he "thought" this was a 12:5.1 compression motor but he wasn't sure. If it has block filler in the water jackets, can it be removed by hot tanking? Any help you guys can give would be much appreciated. I have to pay the rest of the money for it and pick it up on Monday by noon or its gone. Thanks
Soundds like a good find, if the money is right. How is the crank? Steel or cast? Tall deck is a totally different animal from a real L88. Easy way to to tell is plop an intake from a normal BBC on it and see if the bolt holes line up. If it is a tall deck, you can get a stroker crank and stretch that baby out to around 600 cubic inches! That block fill stuff has it's place but you need a hell of a radiator to keep it cool on the street.
I have a 454 dualquad intake made out of a blower base and tunnelram top and he looked at it and said it wouldn't fit without adapter plates.
If the numbers are accurate I found a place that says it should be cast, crossdrilled and have 3/8 bolt rods. balanced for 12:5.1......I have yet to see for myself. You know the old story if its too good to be true.....I'll wait and see but I'll have $1200 in it if its real.
the grayish hard stuff, is Hardblock.. they put it in the block to keep the block from distorting in high horspower/high compression engines, generally dragracing.. the cooling system will only cool the heads and top portion of the block... You probably wont want to run it on the street.. tall deck blocks are used in conjunction with stroker cranks to make what they call mountain motors, generally 500ci and up..
The tall deck probably used a longer rod, which gets away from a lot of rod angularity and creates a motor that lasts a long time in a truck. The useable street parts; crank, rods I guess, heads? What heads does it have? You can get a 454 block and use the crank, almost certainly forged steel.
Tall deck blocks were used in trucks .. if its a real L88 im guessing it should be a 4 bolt block too?... From what I was told the only 4 bolt 427 blocks were in corvettes .. I had one in an 18ft jet boat back in the 70,s.. Lot of motor.. Dave
Cast crank and 12.5:1...recipe for disaster at anything over 6000 RPM and that's even short-lived. Tall deck L-88? To my knowledge, other than perhaps some oneoff toys from the GM Tech guys, NEVER. Tall deck truck motors used taller pistons with an extra ring. The deck is .400 taller than a standard MK IV block. Many are indeed 4 bolt mains and forged cranks and usually that's the extent of the "glamour" in these things. Tall deck blocks make a good 496 platform which is (I think) .060 over and a 4.25 crank. Hardblock has been run on the street by many here in Motown, land of the midnight drag racer. The big problem, and I mean a REAL BIG problem is the heat generated to the oil. Cooling in general is OK but deeper in near the crank the block stays hotter and passes that heat to the oil. Many of the most bad-ass filled block racers used a combination of heavy race oil and oil coolers to keep em alive, but some of them would routinely consume parts at an alarming rate to the average racer. I don't mean to piss on your corn flakes here, but what it appears you're getting is a marriage of convienience. There was a crank, a block, and some other stuff laying around, maybe from a cast-off effort from the past judging by the block fill. At $1200 I don't see a bargain here unless you've left out some major details, especially a cast crank and needing rods and pistons. I'd keep looking. I did some digging around and It appears something's off. Eithe the #s are wrong or the seller is wrong. The block # is not a tall deck and may just be a genuine 427. The crank says forged not cast. The rods in this thing should have been "dimple" rods with 7/16 bolts. It's immediately apparent looking at a tall deck. There's .400 more deck at a right angle to the water pump hole, sometimes easier to tell where the ID pad is at the right front. I'd go see the #s in person as well as the motor and double check all of it. Your description goes against the #s.
A tall deck and 67' lL-88 427 do not equal out. It seems that you stumbled onto someones attempt to unload some parts. I'm not sure what your goal is, race and have a 12 second car, cruise the street with a big block or what? The filled block would turn me away if I was building for the street. Highlander has given good information. I would suggest determine your goal and go from there, it's not traditional but I like the idea of the 572 where you get power and streetablity for about 12.5k last time I checked. I recently acquired a 69'correct #d Corvette 427 rebuilt turnkey for 5,000. Sometimes it's worth saving and buying up to avoid frustrations. There are deals out there but let the buyer beware. Thanks to HAMB input you can get good direction. Good luck and hope this helped you. . Oh, I'd pass on this one!
Wow thanks for all the info guys! (gals?) I went today to look at this motor. He led me down into his basement and at first I wasn't hopeful. Dark dingey mess. Then he pulls back a blanket and we walk into a clean room FULL of big blocks. He shows me several and says if anything he ever sells is bad just let him know. We look at the one and he starts reading off the numbers. Then he yells for his kid. Appearantly the one he was wanting to sell was not THIS one. It's set aside and he leads me to a box in the corner. He shows me a block and apologizes for his son giving me the wrong numbers from parts he wants to keep for himself. He shows me a block that is clean and still has cross hatch in the cylinders. He points out that it is a truck 427 tall deck and hands me a print out from the web This block cast # is 473478. Truck heavy duty. It has 4 bolt mains. He shows me the crank and it is clean and looks like its a forged crank but not sure then he tells me that it is a hi perf forged crank and I should be able to tell by the fact that the number on it only has 4 digits. (6223) I'm starting to get the feeling that he is pulling a bait and switch. But there are probably 10 chevy big blocks here and I'm still intrigued. So I tell him that I'm not willing to pay $1200 for some mismatched parts. And he says I can take all the parts to any shop of my choice and do any work I want done to make sure they will work before I pay in full. I had already given him $200 yesterday. He shows me the rods and pistons and they look fine but the wrist pins are very stiff. (?) And there is a gummy feeling to them. He says its from the alcohol? The pistons have very little black on the tops and have not been cleaned. they are stamped z-16. They appear as flat tops with one valve relief cut. He says for me to take the block, crank, rods and pistons and call him when I am satisfied that they are ok. I asked about the block filler and he says that was the other block not this one and he's right. This one is empty. I am to get the heads when I pay the rest of the money. He says they are rectangle ports and were on this motor. I saw them but didn't look them over too close. NOT aluminum for sure, just regular cast with very little build up and had double wound valve springs. So as it stands I have the short block parts in my suv for $200. If its junk he'll take it back and refund my money. Or I can pick any motor in his basement except for 3 along one wall. We'll see what happens. Sorry for the long post but its late and I'm bored. As for my goal? I am putting together another 55 desoto but this one is going to be done as a gasser. I have a drilled straight axle with disc brakes, ford nodular 9, with 3:93 gears, Mickeys on 15x15 rims still looking for a th350 and a stall (2400?) I'll probably only take it to cruise nights and such but I want it to be as real as it can get but keep some streetablilty. I don't intend on turning this motor over 5-5500rpm. So I will be in search of the right cam. I have a dual quad intake but will need spacers for it. I have a noisey gear drive and 1.75 ratio roller rockers. Everything you guys tell me I take to heart. I have built many small blocks and had some extremely fast cars but I'm new to BBC's and this will be my first gasser as well. I'm aware that they are a handling nightmare and won't be doing any high speed corners. I just love the look.
Tall deck, I'd say no. Not for what you're looking to do. Like I said above they make a nice 496 but they're more $$$, custom parts, machine work, not worth the drill when the same can be built in standard deck. Look at the base of the cyls in the crankcase area. They may or may not be relieved for a 4" crank. Depends on the year of the block. Sq port heads...low performance? I'm laughing as I type this. For what you want to do ANY port size is gonna be more smiles to the gallon than you can bear. If you're lucky the heads on this get up might be the best thing in it. The sq ports were open chamber and closed chamber. Closed chamber with a flat top will give about 10.5. Cam selection will be the key to the fun factor. I'll go out on a limb here and say that the BBC is far and wide the easiest engine to build, EVER. There's really no reason at all to invest a shit ton of money in combining odd parts to go fast. 427, 454, who cares? All the outside dress is identical. The last stock based BBC I did was years ago. A basic LS-7 short block with a non-twist crank and dimple rods, TRW/Speed Pro "out of the box" pistons with a 50cc dome, .714 roller cam. I did spend on Merlin sq ports, a Dart intake, and a used Dominator. We made something in the way of 710-725 HP or near 600 RWHP. With 5500 stall and a brake I got 1.42 60' times and 10.32 @ 130MPH in a car that weighed 3545. BBCs are easy. I know prices are up on aftermarket stuff. Shop around. I wouldn't jump in with this tall deck get up. Add to the mess that once you're done with it not many people want it so it's almost good $$$$ after bad.
My whole reason for even going with a 427 of any kind is just because I can. Around my area you mention 427's and people snap their necks to take a look. I could have picked up a 336 truck motor for $900 running, but no one has really ever heard of it. I just like something different but not so rare that I couldn't afford to build it. Caddy motors around here are too rare, Hemi's don't exist except in magazines and mythical friends garages. So this is the path I chose. I'm not looking at running this thing down the track, I just want it to be able to and look like it has lived it's whole life that way. The straight axle only cost me $150 complete disc to disc. with Springs! If it seems like a boat anchor I might just build it mild and sell it for something else. We'll see. Completely rebuilt fresh it should bring me $1800-$2000 around here. Thank you all for the input, I really appreciate it.
I like the tall deck motors, and if he is giving you a tall deck motor with rectangle port heads for $1200 - that is about average. The entire worth there are in the heads - they go for near $1000 around here. 427 truck blocks - about $200, 427 truck cranks - about the same. If you run alcohol without top end lube, it will wash the oil off and you get galling. With a tall deck, toss out stock rods and pistons. Here is a couple of tricks to building a killer tall deck. First off - figure out your stroke. If you are going to use the stock 3.76" 427 crank, then use a 6.8" aftermarket rod and a 496 piston. This will give you an off the shelf zero deck motor. Otherwise run a 4.25" stroke crank kit designed for the tall deck block and get 496 cubes with a 60 thou over bore. If falls right into the block with no clearancing. For intakes you will either have to use spacer plates, or find a Weiand tall deck team G that fits your heads. They recently stopped casting them but still has stock as of a few monthes ago. I have a 7528 for my 427 tall deck motor - 4150 carb, machined for a standard distributor, and oval port heads since that is what I am running.
Like others said "if you can afford it build a 496"" w/ rect. port heads, this wil be a great running motor. If your friends are impressed w/ a 427, what are they going to think about a 496!?! Although I see you're putting this in a 55 DeSoto and that's almost a sin (Chev motor in a Mopar), you should be piecing a 392 (or other) Hemi together for it! If that's not cost effective run a 383 or a 440 which will probably the same price (or cheaper) as a bbc... just my two cents.
For what it's worth, the 6223 crank is a forged shaft with a 3.76 stroke (can be used in 396, 402, or 427 engines).
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