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Discussion Starter · #1 ·
Its a sunny day mid 60,s. and I have really been taking advantage of it. no firewood to cut. caughtup on most everything. So today I went to work on my 71. The valve seat came loose and the 402 dropped a valve and destroyed a piston and cracked the cyl wall. I already have a low deck 454 I pulled from a 78. So today I got busy and pulled out the 402 and stripped all the parts needed to install the 454. things like engine mounts brackets & pulleys ect. The 454 already has the proper flywheel. got the 454 stripped and quit for the day. I going to get some degreaser and oven cleaner and clean up the 454 and the engine bay and chassis on the 71. I left the turbo 400 trans in the truck. And took out the 402 engine without removing the hood. plenty of room. haven't decided whether to go back with the factory cast iron manifolds or a set of hedders thatI already have. The exhaust on the truck now is small 2 inch pipes and glass packs. I want to install turbo mufflers & bigger 2&1/2 inch pipes the 454 has square intake port heads with a edelbrock dual plane high rise intake. at least the gas is cheap enough to afford to drive a truck with 456 gears and a big block engine!
 

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Sounds like your having fun. That 454 should make the 456 gears hum. We had 50 degrees today and more tomorrow but rain is coming in. Thanks for the update. Sweet sounding project.
 

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Discussion Starter · #3 ·
The 71 is a 3/4 ton. it has a flatbed and goose neck ball in the bed. ive hauled some heavy loads of scrap in it. the last picture is the damaged cyl. it likely could be fixed with a sleeve. the cyl bore has notches cut out above the ring grove. maybe to lower compression like they did on the 348 truck engines?
 

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Discussion Starter · #5 ·
ive got a good 69 396 block. I might get it bored .030 and use the crank and pistons from the broke engine. I will need one piston and possibly a rod. and need to weigh it to be sure it weighs the same as the other 7. ive got several sets of big block heads. The 402 used plenty of fuel. I doubt the 454 will use more? Ive also got a 366 high deck engine. and I really thought about installing it in the 71.
 

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Ya might know different, but from what I understand, a 30 over 396 does not come out the same as an actual stock 402. Now I was told this years ago by a machinist. I remember the old story of a pile of 396's at GM being bored 30, and put on the market as a 402. Now in the truck with the 402 the badge on the side always read 400. The true 402 was in the Camaro and later like 71 in the truck. I have one from a 71 that's a 402, and another from a Camaro. Remember the 71 heavy Chevy ?
 

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Discussion Starter · #7 ·
Ya might know different, but from what I understand, a 30 over 396 does not come out the same as an actual stock 402. Now I was told this years ago by a machinist. I remember the old story of a pile of 396's at GM being bored 30, and put on the market as a 402. Now in the truck with the 402 the badge on the side always read 400. The true 402 was in the Camaro and later like 71 in the truck. I have one from a 71 that's a 402, and another from a Camaro. Remember the 71 heavy Chevy ?
a 402 crankshaft has different balance on the crankshaft counter weights to accomidate a slightly heavier than a stock 396 piston rod assembly. the 366 truck 396 car 402 car 427 car and 427 truck all have the same diameter rod and main journals and the same stroke. however they are all balanced differently. they will fit but would vibrate. they do not interchange. using my 402 crank in a bored .030 396 block is a 402 and if I use the matched pistons & rods will work perfect. My truck also has a 400 badge on the fender.
 

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See that, I didn't realize the cranks were weighted differently. I know the 454 was an external balance crank, but always thought you could just swap out cranks from the others, without changing rods.
I think at the time I was being told about 402/396 I was going to order 30 over 396 Pistons, for my stock bore 402, to put a dished piston to lower the compression ratio, so I could run a supercharger. He informed me they were different part numbers. But this is why I stick to sheet metal, it's something I understand a bit better. :)
 

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This is good info, I had not known this, so if I decide to go 402, I will need to verify part numbers....I`ll start looking now....anim_63
 

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Discussion Starter · #10 ·
Any crankshaft can be balanced to any weight rod & piston combination. notice the holes drilled in the counterweights. Those are for balance. to make the counterweight lighter you drill holes and remove metal. to make them heavier they add moly fill material that weighs heavier. They attach bob weights to the rod journals that weigh exactly what the piston and rods weigh. spin it in a lathe and adjust the weight of the counterweights. The only place I know who can actually do that correctly is Racing Head Service in Memphis Tenn. Im certain there are others that im not aware of.
 

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Old Truck Man <------- insert name here :D I've seen this done at a friends machine shop/Speed shop, Terra's Speed Shop In Bloomsburg Pa. We contract Lou for all our building need. I watched them balance my entire assembly. The crank is really interesting to watch. Quite a few years ago he upgraded to a computerized balancer. It really is a some what time consuming job, and definitely needs a seasoned builder at the helm....
 

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Discussion Starter · #12 ·
Well I back at swapping the engine in my 71. The weather has gotten warm Its 84 degrees. So I got out my power washer (ive had it winterized) and have washed the engine bay and the 454 engine. Sprayed some oven cleaner on the crusty bits. This evening I will paint the engine and touch up under the hood. I left the auto trans in the truck. Its being supported by my transmission jack. ive pulled the water pump and front pulley from the balancer. That way I can shoehorn in the engine and not have to disconnect the air cond evaporator. When I was young I often would swap out a engine in a day. Now old age has slowed me down considerably.
 

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When I was young I often would swap out a engine in a day. Now old age has slowed me down considerably.
anim_63 funny how age really slows us down, what used to take an hour now takes several hours....
 

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a 402 crankshaft has different balance on the crankshaft counter weights to accomidate a slightly heavier than a stock 396 piston rod assembly. the 366 truck 396 car 402 car 427 car and 427 truck all have the same diameter rod and main journals and the same stroke. however they are all balanced differently. they will fit but would vibrate. they do not interchange. using my 402 crank in a bored .030 396 block is a 402 and if I use the matched pistons & rods will work perfect. My truck also has a 400 badge on the fender.
mine does as well
 
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