Building a mild 438 for a 68 Road runner. Hoping for maybe another 100 HP over the 383. Had about decided to spend the bucks on a good converter. Way back in the day my 383 was near stock with a long duration Crower Monarch cam. Sounded and ran good, but with an automatic it was hard to hit a happy medium between idling in park and cutting off in gear. In my research it's sounding like a stock 383 Road Runner converter is not a bad choice for a street cruiser (Mostly). The 438 will have a little more lift and duration than stock, but under .500 lift and .300 duration. .323 gears, 70 series tires. Also back in the day and by accident I replaced the 440 converter in a GTX with one from a 383 Road Runner because it was what i had. The X would smoke the tires effortlessly with the smaller converter. I see converters rated at 2200, 2400, 2500, etc. I'm reading the 383 converter is already there.
its now 2024 and converter technogoly has come a long way since the 70's and 80's. my opinion would be to call dynamic, ultimate or ptc and have a converyer built for you car, combo and intended use. be 100% honest about everything when talking to them.. the converter won't be cheap but the difference it can and will make is incredible.. i always laugh when i see someone dump thousands into a motor and trans only to skimp out on a conveter. the conveter can make or break the entire combination..
