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Swap the mercruiser 240 5.7L 350 for the DZ302?

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Discussion Starter · #1 ·
I just got my hands on a genuine DZ302 and man am I excited to build and slap that bad boy in my truck. I'll pull the mercruiser 240 out and put that sucker in and bam high rpm monster. What do yall think?
 

· Two tones of terror
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I would not put that in an S10, that belongs in an original Z28.

You could sell that thing for a boat load of money right now and build yourself a 383 or 406 with a Dart block and AFR heads and could pay for it all with what you would get for that.

It would run circles around any old 302 and be fun on the street/strip.
 

· Been there Done it
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To be street compatible you'll need a T56 because that engine will want some really tall gears. A friend of mine had a 67 Camaro with the 302. That year they were a real sleeper. No Z28 markings. Very plain looking car. They only made a few that year, primarily for Trans Am Racing. His got totaled when a guy ran a stop sign in front of his wife when she was driving it. IIRC it came with 4.10 gears, but could have used 4.56. I remember guys putting 5.13 in for strictly drag racing.
I agree with @KJF95S-10 that you can get a small fortune for it from someone doing a numbers matching Z28 restoration. It appear as though you'll need to go completely thru it. Which won't be cheap. A restorer won't care.
Take the money and buy a crate motor with more power for your truck. Torque is what you feel on the street because you rarely get a chance to get into high rpms. Where that engines power is.
 

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Take the money and run! That mill is worth a lot more in a '69 Z28 than it will ever be in any S10. I have a running 454 that I'll swap you, straight up.
Once it's been rebuilt and the block is decked, it'll just be another engine.
Oh, and a true Z28 is a **** to drive. It makes its power high in the range and is a dog on the bottom end. I've driven a couple and don't care for the street manners at all.
 

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Check the casting numbers on the crank and balancer. The pad pictured above the water pump mount does not look like the pad GM used in 69. The early blocks had a long & thin pad, the square one pictures was used much later. Also, it is hard to see, but if the DZ is to the left of the pad, it looks like someone stamped it themselves.

Sorry, but I do not think the block is a real 1969 camaro 302 block.
 

· Horsepower Addict
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The larger size letters before the serial number & the stampings above look suspect.

You can get more info by looking at the date codes on the heads & block.... they are letters for the month, then date & year.
Example C 16 9 is March 16 1969.

Also measure the valve sizes on the heads because those were used on tons of engines with 1.94 valves.
 

· Two tones of terror
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The intake valves should be 2.02" with flycuts around the chamber for unshrouding. I think real 302/LT-1 heads also had screw in studs and guide plates which yours do not, unless it was a 1970 only thing.
 
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· Two tones of terror
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After looking at it I don't think this is a DZ 302 at all. DZ would be the suffix code like pictured above. Not two random letters stamped before the vin. Someone tried to pull a fast one and get top dollar for this block. Your suffix code is TBM which translates to 1970 conversion van with a 307. Trucks and 300+hp cars got the 010 block casting too which is a great oem block to build. I say go for it.
 

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DZ sounds cool, good bragging rights, however unless you plan to do all your driving at 5 or 6 grand with your rear end sliding around, it may not be worth actually doing. I think your answer is above, the suggestions of bottom end torque.
 

· Been there Done it
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Don't quote me but I always thought the 010 designated a 4 bolt main block also. ?
No there are all kinds of urban myths about the 010 block. Some folks swear it's 10% nickel. Not true. The one true thing about it is there were probably more of that casting number built than any other because it was around a long time and was used for all kinds of engines. 302, 307, 327, 350, 2 and 4 bolt. Not sure if it was used for the 262 or 305 V8's like the ones in the Monza's.
 
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