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73-87 Chevy _ GMC Trucks => Performance => Topic started by: kmcbride74 on February 07, 2011, 09:30:34 pm
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Folks,
Relatively new to the forum. I have an 85 c10 2 wheel drive, lwb, original 305, and it is some kind of tired. My goal is to replace the motor with something with some more power but nothing ridiculous and on a pretty tight budget.
I purchased a 350 and TH350 from a friends 74, stamped on the block->GM 3970010 and stamped in front of the passenger side head->V0211TMM. I verified it is a 4-bolt motor and it seems to be in decent shape sans some leaks which I will fix with a gasket kit.
I picked up a 2101 edlebrock performer intake, some headers, and I'm going to go with the Eldelbrock 1406 600 cfm carb
I am also looking at the Edelbrock 2102 cam.
Based on my research of the stock motor above, it had 145hp. With the 4 barrell upgrade and others mentioned above, will that get me closer to 200hp?
Any rough ideas? I know it'd need to be dyno'd to be precise. I'm just trying to see what sort of extra juice I can expect from this before diving in.
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First off I assume you checked your local laws and it is OK to swap a 74 into a 85 and have it still pass smog, since you mentioned headers. The other things I would consider is an HEI distributor and maybe a cam. My 74 is pretty weak, that is why I am going to swap in another one, and eventually rebuild my 74.
Welcome to the site by the way from California.
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Ya check your smog/inspection laws first. Usually you can put a newer engine in a older vehicle, but not the other way around.
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confirmed on the inspection requirements here in Texas, through a friend who works at the dealer and an inspection station near the house. Now, the performance question? Thoughts?
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Did your '85 come with a 700r4 or th350 transmission?
I'd do a compression check on the motor before doing too much. If the 350 is tired too, you won't see a lot of performance from putting more cam in there. You'll notice a good difference, that's for sure and it'll wake up that long bed. Budget in some cash for the muffler shop modifying your exhaust system to match up the headers too.
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yep, safety only inspection on anything older than 25yrs in Tx.
What you have planned should wake up that truck nicely. But like suggested above, do a wet and dry compression check on the engine before throwing any parts at it.
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Thanks for the inputs guys. I'll surf around, but if anyone has their finger on a 'how-to' set of instructions for the compression check, I would appreciate it. I've never done one. I assume there is a tool needed? PS: To be clear, the motor is on a stand in my garage right now while I clean it up.
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Perform a dry compression test...Do a compression test like so:
Install a battery charger to maintain consistent cranking speeds.
Pull out all the plugs after you warm up the engine.
disable the coil by unhooking the B+ lead
Crank the engine for 4 complete compression strokes at WOT (Wide Open throttle) You'll see it pulse 4 times on the gauge or hear the starter strain 4 times at each compression stroke.
Record your results for each cylinder on paper and post your results.
the only tools you need are a compression tester you can rent one form a parts store or buy one and a sparkplug socket to remove the spark plugs and a charger if you have one
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Uhh, it's gonna be kind of hard (impossible) on the stand, cuz you need to be able to turn the motor over, so you'll need the starter and flywheel connected to the engine.
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Ive seen people run their engines on engine stands, so just hooking up the flexplate and starter wont be a problem
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hmmm, fuel, coolant, any way to test compression with the motor off? No way to test by spinning the fly wheel manually?
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Ive seen people run their engines on engine stands, so just hooking up the flexplate and starter wont be a problem
Really? I wouldn't trust that setup. I saw somebody bump one over that was on tires and blocked with wood. Flopped right over onto the concrete...haha
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Ive seen videos on you tube. If your just cranking for compression, you dont need fuel and coolant. I dont think you check compression with the engine running.
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if its on an engine stand; I would remove the heads and look, check for a ring ridge too.
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Since you check compression by taking the spark plug out and you are suppose to pull the coil wire, it would be great to see it run that way. 8)
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Funny as it would be (eventually) to see the engine torque itself right off the stand or tip it over, I am NOT going to do this. I will take my chances. This engine did come out of a friend's truck who vouches for it. He was replacing it to upgrade to a fuel injected motor.
BTW, this will be my first motor swap on one of these. Assisted by two buddies who have done several. Any guidance from anyone who has done something like this is appreciated.
I'll try and take some progress photos as I make headway and post them somewhere here...
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You can do a cylinder leakdown test without cranking the motor. Don't know if you can rent those or not, but there's a cheap set at HF. Whether you trust the guy or not its a bit risky to put in an old carbureted motor without checking it out. Let us know how it works out for you.