Big Block Transplant
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Instructor
Joined: Sep 2013
Posts: 118
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Big Block Transplant
I have the opportunity to buy a complete 1995 Chevrolet dually w/454 motor. Running w/139,000 miles on it. Purchase price for complete truck is $1000.00. Transmission went out. Does this sound like a decent investment to finally score a big block for my 71 C3? Any advice would be appreciated!
Racer
Joined: Nov 2017
Posts: 289
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I have the opportunity to buy a complete 1995 Chevrolet dually w/454 motor. Running w/139,000 miles on it. Purchase price for complete truck is $1000.00. Transmission went out. Does this sound like a decent investment to finally score a big block for my 71 C3? Any advice would be appreciated!
I'd it in a heartbeat just for the engine alone.
Safety Car
Joined: Apr 2005
Posts: 3,624
Likes: 431
From: Dale City VA
1995 is a MKV 454. No mechanical fuel pump provision on the block, so you will need an electric fuel pump. 1 pc rear seal, so it takes a special flywheel. There are a few other things about that generation of BBC that make it different from the ones that came in C3s but it will bolt in the car fine.
Do you plan to build it or install as is?
Will
Do you plan to build it or install as is?
Will
Race Director
Joined: Jul 2015
Posts: 13,082
Likes: 3,399
From: SW Florida.
Peanut heads. Dished pistons. I can buy that block for 200 bucks. You want a gen 6 L29 or any MK 4. With those you get flat pistons and you can run early heads better on the gen 6 than the 5. Still no fuel pump boss. L29 heads are better than round ports, but still not high perf heads. But the valve seats take today's gas. Big tough inconel exhaust valves. Good street heads. Little 100cc ports. Vortecish swirl chambers. And the valve guides are 20 years younger than 049's and 30 years younger than 215's. Smoke tires at the drive in all day. Won't get you under 12 seconds though...where are you located?
Last edited by derekderek; Nov 11, 2017 at 11:56 AM.
Safety Car
Joined: Aug 2000
Posts: 3,909
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From: Clymer PA
I don't believe 454 blocks came in the tall deck (10.2). The problem with the Gen V block isn't the deck height, it is the different location of the cooling passages (if I recall correctly). The Gen IV heads won't work with the Gen V block making your head selection very minimal. The correction was made with the Gen VI block allowing the use of the Gen IV heads. That's likely why Mark said he would not buy the motor. Without a good set of heads as an option I would agree.
Race Director
Joined: Jul 2015
Posts: 13,082
Likes: 3,399
From: SW Florida.
you can run any bbc head on a gen 5. have to be careful what head gasket you use. but you have those low compression dished pistons and crappy little round port heads. and no, a tall deck truck motor is not a pick up truck motor. it is a C40 and larger big truck motor. 366 and 427 only. great for 4.5 stroke boat motors. but I would not waste time, money and space on this truck. can't run the long water pump, so all brackets and alt-p/s-A/C useless. you will end up using the block and crank and getting scrap price for the rest. there are MK 4 engines out there for 4 to 600 bucks.
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Burning Brakes
Joined: Jan 2007
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From: Lighthouse Point FL
Instructor
Joined: Sep 2017
Posts: 169
Likes: 20
From: Westlake Ohio
Red, I'm tickled to see someone else slipping a big block into their C3. I just finished shoeing a 454 into my wives 76 racer. I have built dozens of BBC engines for everything from Chevelles to Camaros to front engine dragsters. If you want to slip a stock bbc into your car I'd go with the 8.1 tall deck engine. GM finally did it right with this tire shredding torque MONSTER. If you like tinkering, any MarkIV big block with 074 or 781 heads (easy to find) Will be money well spent. Then look up some LS6 or LS7 old school big block combinations and you will not be sorry. PM me if you would like more info.
Drifting
Joined: Jul 2015
Posts: 1,765
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From: Catlett VA
I have a 454 Mark IV from a 1978 truck in my 68 convert. With the add-on mods installed by the PO (roller rockers, Comp cam, Hedman headers, improved intake, 750 cfm carb) I got 306 rwhp with those little peanut port heads and low compression pistons. I installed aluminum square port heads, different cam, better intake, HEI ignition and am up to 355 rwhp. Winter project is to swap out the pistons to domed pistons to get 10.5:1 CR and another 40-50 rwhp. Your Mark V engine may limit your add-ons, so see if you can find a Mark IV or Mark VI for the same $$$.
Race Director
Joined: Jul 2015
Posts: 13,082
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From: SW Florida.
Milan, have you put an 8.1 into a C3? I thought the extra deck height made fit hard and headers fitting even harder. and that valve cover is damn close to the master cyl already. .4 higher, I dunno.
Last edited by derekderek; Nov 14, 2017 at 05:29 PM.
Instructor
Joined: Sep 2017
Posts: 169
Likes: 20
From: Westlake Ohio
Derek you are spot on. A hydroboost and custom header work would be needed unless you use stock manifolds. But for turn key retina detatching torque it might be worth it. Tall valve covers worth with a regular bbc so??? Lets face, it either approach would require a comprehensive plan. But to your point I have not installed a tall deck in a c3.
Last edited by Milan454; Nov 14, 2017 at 07:47 PM.
Drifting
Joined: Jul 2015
Posts: 1,765
Likes: 254
From: Catlett VA
Milan454 said "But for turn key retina detaching torque it might be worth it. "
I have the 8.1 L in my GMC 2500HD and even with the weight of the truck the torque throws you firmly back into the seat. I have a Mark IV in my 68 convert and while it has good torque, the 8.1 has a lot more.
I have the 8.1 L in my GMC 2500HD and even with the weight of the truck the torque throws you firmly back into the seat. I have a Mark IV in my 68 convert and while it has good torque, the 8.1 has a lot more.
Intermediate
Joined: Jul 2011
Posts: 45
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From: Cedar Rapids Iowa
I have a 454 Mark IV from a 1978 truck in my 68 convert. With the add-on mods installed by the PO (roller rockers, Comp cam, Hedman headers, improved intake, 750 cfm carb) I got 306 rwhp with those little peanut port heads and low compression pistons. I installed aluminum square port heads, different cam, better intake, HEI ignition and am up to 355 rwhp. Winter project is to swap out the pistons to domed pistons to get 10.5:1 CR and another 40-50 rwhp. Your Mark V engine may limit your add-ons, so see if you can find a Mark IV or Mark VI for the same $$$.