first time 327 buildup

hey everyone how is going?This is my first time trying to build an engine.I know a guy who has been building sbc's for a good while, and bought some parts;a crower billet steel crank (3.250 stroke) carillo 5.7 inch rods and je forged aluminum pistons with a 12 cc dome and air flow research 195 heads with 74 cc chambers.The block i got is from a 350 goodwrench engine.He said that this will work , but some one else told me that 327's need 6 inch rods or 6.125. Is that true?And how much power will a factory block handle before is breaks?I also plan to put a shot of nitrous, about a 150 or 200 shot to help ad some torque.Any help would be appreciated.

no- you don't need 6" rods for a 327. But you may want to get a shovel. Domed pistons will push your compression up too high for a 200 shot of Nos, and your gonna side load your je's.

It is unlikely you will need 6" rods unless the pistons are designed this way. Some aftermarket pistons, mostly for turbocharged engines, could use the 6" rod. But, you said 12cc dome, so nope, standard small block chevy rod size as these would never be used in a boosted engine.

Crower crank huh? Wow...that was expensive. Most likey was a circle tracker to be using the shorter stroke. Make sure the main journal size is larger than 2.3" or you're not gonna slip that $$$ crank into a 350 block. Most 327's found today are small journal and did not interchange with the 350 blocks, but you're talking afermarket, so it may have been designed for medium journal blocks.

Domed pistons increase compression, but the heads have larger chambers, thus reducing the compression. To be safe, if you want to run pump gas, try to say around 10:1 or less on your compression. Otherwise, you'll get spark knock or have to run really high octane fuel (or other means of reducing spark knock).

If you're looking for comparision regarding 327's, I run a "true" 327 engine (1963 block and crank) supercharged with dual stage nitrous for low end giddyup (total 250 HP added) to make a 600+ HP engine. It turns 7000+ R's and it's still together! But...the bottem end was built to handle it. Factory 327's made up to 370 HP without forced induction, so you can kind of get an idea on what you need to do from there.

Hope this helps.