Guest RXO510 Posted October 30, 2001 Share Posted October 30, 2001 First off thanks for everybody's help. Really appreciate it. We have a '71 240Z with a 350 or so we thought SB. Had a powerglide so we immediately swapped that trans for a TH350 with a B&M converter(2400). Also threw in a B&M pro ratchet for him. We will be getting a bigger cam soon so we threw that trans converter combo in. Well when we swapped the trans I noticed that the flexplate had a counterweight on it. I thought I read somewhere that the 350 usually doesn't come with a conterweight but a 400 crank does. Is this true? I've been working on rotaries for 16 years and the V8 scene is very new to me. Just trying to learn and we are learning. So I was just wondering if I had a 400 SB or possibly a stroker motor. Well I checked the stamped numbers on the block and it's for a 350 SB from a Camaro or Corvette. (Read how to check the block from a previous post.) If the counterweight was on a 350, wouldn't the bearings get messed up due to that counterweight? Just trying to learn. Thank you. Quote Link to comment Share on other sites More sharing options...
Guest kc6wfs Posted October 30, 2001 Share Posted October 30, 2001 Hello, Congrats on the car. The newer block 350's do have a counter weight on the flex plate. I have a 2000 Vortec 350 motor and use a flexplate for the ZZ3-4 brands of motors and it has a counter weight. No problems yet. Dave Quote Link to comment Share on other sites More sharing options...
Guest RXO510 Posted October 30, 2001 Share Posted October 30, 2001 Hi Dave. Thanks for the information. I doubt that this block is a newer crate motor that is why I was wondering why I have this counterweight on the flexplate. The serial numbers from the block are refered back to an older Camaro or Corvette. We really appreciate your input and information. Learning something new everyday. Thanks again, James & Gabe Quote Link to comment Share on other sites More sharing options...
Tim240z Posted October 30, 2001 Share Posted October 30, 2001 Check the damper too. If it has weights on it too, that's a dead give away for a stroker setup. Tim Quote Link to comment Share on other sites More sharing options...
Guest RXO510 Posted October 30, 2001 Share Posted October 30, 2001 Hi Tim. Thanks for the tip. I will check that out later today after work. Learning something new everday. I love it! Quote Link to comment Share on other sites More sharing options...
pparaska Posted October 30, 2001 Share Posted October 30, 2001 It could be a 350 block, but a turned down 400 crank, making it a "383". IF the crank was not internally balanced ( a good bit more money to do to a stock crank, and usually not worth it), then it would have a 400 balancer and flexplate. The balancer is hogged out on part of the circumference, so that should be easy to tell. Quote Link to comment Share on other sites More sharing options...
Guest RXO510 Posted October 30, 2001 Share Posted October 30, 2001 Hi Pete. Thank you for the info. I will check this out as soon as I get home from work. I'm just enjoying and taking in all the information that I can. Thanks again! Quote Link to comment Share on other sites More sharing options...
Guest RXO510 Posted October 31, 2001 Share Posted October 31, 2001 Took at look at the balancer and looks like about an 8 in circumference, (from a 400 crank). I read and heard that the 350 balancer is like about 6 1/2" So I'm thinking I have a stroker motor now. I guess that's what Pete meant by the balancer being hogged out? I just don't know if the bottom has been bored out to make my block a 383 or 377. But for now we will change the cam, lifters and carb. Drive around and have fun. Suspension upgrades and brake upgrades are next. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted October 31, 2001 Share Posted October 31, 2001 rxo510, the diff of 383 or 377 is the block and crank combos used.....383=400 crank and 350 block....377=350 crank and 400 block.....but the best thing to do may just take the pan off and get the casting # off the crank if your that curious... Quote Link to comment Share on other sites More sharing options...
Guest RXO510 Posted October 31, 2001 Share Posted October 31, 2001 Thanks for the info Gearhead! I definitely have the 350 block according to the serial numbers from the block. From all the info I got today; looks like I have a 400 crank. I thought that the cylinder bore size also played a factor in the engine displacement. So if I have a stock 350 bottom end with a 400 crank = 383? Doesn't the bore size matter to make it into a 383? Wow learning more and more everyday! Quote Link to comment Share on other sites More sharing options...
Modern Motorsports Ltd Posted October 31, 2001 Share Posted October 31, 2001 "So if I have a stock 350 bottom end with a 400 crank = 383? Doesn't the bore size matter to make it into a 383" Yes, and the bore size is referenced as the block in above note. Here's a summary (displacement being area of cylinder (3.14 times r(radius) squared) times stroke of crank x 8 cylinders) Chevrolet V8 Bore and Stroke CID Bore Stroke Notes 262 3.671" 3.10" (5.7" rod) 265 3.750" 3.00" ('55-'57 Gen.I 5.7" rod, '94-'96 Gen.II 4.3 liter V-8 "L99" 5.94" rod) 267 3.500" 3.48" (5.7" rod) 283 3.875" 3.00" (5.7" rod) 293 3.780" 3.27" ('99-later "LR4" 4.8 Liter Vortec) 302 4.000" 3.00" (5.7" rod) 305 3.740" 3.48" (5.7" rod) 307 3.875" 3.25" (5.7" rod) 325 3.780" 3.62" ('99-later "LM7" 5.3 Liter Vortec) 327 4.000" 3.25" (5.7" rod) 350 4.000" 3.48" (5.7" rod) 350 4.000" 3.48" ('96-'00 Vortec, 5.7" rod) 350 3.900" 3.66" ('89-'95 "LT5" in "ZR1" Corvette 32-valve DOHC) (5.74" rod) 350 3.900" 3.62" ('97-later Gen.III "LS1")(6.098" rod) (actually totals 346 cubic inches) 364 4.000" 3.62" ('99-later "LQ4" 6.0 Liter Vortec) 383 4.000" 3.80" ('00 "HT 383" Gen.I truck crate motor) (5.7" rod) 400 4.125" 3.75" (5.565" rod) Two common, non-factory smallblock combinations: 377 4.155" 3.48" (5.7" or 6.00" rod) 400 block and a 350 crank with "spacer" main bearings 383 4.030" 3.76" (5.565" or 5.7" or 6.0" rod) 350 block and a 400 crank, main bearing crank journals cut to 350 size data source, and some 'car math' etc..... hope that helps Quote Link to comment Share on other sites More sharing options...
Guest RXO510 Posted October 31, 2001 Share Posted October 31, 2001 That was some great info Ross. That was printed out and copied and put into my JTR manual. We love this stuff. Yes, that was a great help to us. Thanks again. Quote Link to comment Share on other sites More sharing options...
pparaska Posted October 31, 2001 Share Posted October 31, 2001 RXO, The 400 balancer has material "missing" from the outer circumference, around only part of the circumference. It's amazing what you can find on google.com's image search engine. I typed in "400 harmonic" and found the following: Notice at the 9:30 position at the back part of the outer circumference. You can see where the material is seemingly "missing". [ October 30, 2001: Message edited by: pparaska ] Quote Link to comment Share on other sites More sharing options...
Guest RXO510 Posted October 31, 2001 Share Posted October 31, 2001 Hi Pete. Yes sir! That's what my balancer looks like. Has a big groove just like the one in the picture around the outer edge of the balancer. Google.com. I will be visiting that website also. Thanks again. Quote Link to comment Share on other sites More sharing options...
DavyZ Posted October 31, 2001 Share Posted October 31, 2001 Dude! Looks like a nice bonus! Man, to "accidentally" get a stroker motor, when all you were expecting was a 350...SWEET! Congrats on a good find. That 383 just makes gobs of torque from way down low to way up high. What fun Davy Quote Link to comment Share on other sites More sharing options...
Guest RXO510 Posted October 31, 2001 Share Posted October 31, 2001 Hey DavyZ! Thanks! I'm all smiles and so is little brother. Very nice bonus for us! Fun is the keyword for us. That's what we want and so far it's been fun and informative. Well C.H.U.D. isn't ready for picture taking just yet. We need more work, but when it's done we will have pics of before and after. From CHUD to RIPPED Z! Quote Link to comment Share on other sites More sharing options...
Guest KraZ4spd Posted October 31, 2001 Share Posted October 31, 2001 I hear ya RXO510. That is the best part of this site. Quote Link to comment Share on other sites More sharing options...
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