kinda depends what you want to do with it. you could go the old fashioned hot rod route with multiple carbs, head work, high compression, big cam, etc. Or drop the compression, put a blower on it.
alright im kinda wanting to go more the old school route. but which one would you estimate to cost more?
Build to 300 horse spec and add a 100 shot of nitrous....the best of both worlds, a very streetable machine with a play button.
Buy and read "How to Hot Rod Small Block Chevys" The book has been around for years and it will help you build a great Motor. My brother built a 327 for his 66 El Camino using the book as a guide and man that thing was fast. Ran low 12s in the quarter mile with mufflers and this was in 1977. No Blower, Turbo, etc...just a well built 327 with a Holley double pumper.
Good cam and a good intake and carb with some head work. Those 327s are high revers so hp is easy, torque not so much....
I have a small journal 4 bolt main 327 with a 625 cfm Performer on top of an OEM 69-70 Z28 hi-rise aluminum intake running 2.02 heads, 10.3:1 compression, and a 292 magnum cam that dyno tested at 408 hp. I do have to add octane boost and I wouldn't recommend anything over a 282 cam for an automatic. I have an M22 with manual brakes so I don't have any vacuum issues and I'm running a 3.24 geared posi 10 bolt rear end out of an '83 cop cruiser. I haven't run this combo with the posi rear end yet (just swapped it in)...man am I anxious!
By the way, if you have a large journal 327 and/or a 2 bolt main 327 I would stick to around 350hp. My engine makes most of it's hp over 4,000 rpm and I have had it up around 7,800 rpm. Without lightweight aluminum slugs you really cannot push a 327 that far with risking grenading the block.
Do you have pictures of the small journal 4-bolt block??? If so, please post'em! I've never seen one before.. Thanks!
they dont exist thats why. 4 bolts were large journal only, unless he has splayed 4 bolt caps that someone installed. I built a 4 bolt 327 using a large journal steel crank and a 4 bolt 350 block
If that is a stock 64 250hp 327 and you go naturally aspirated without spray you will need pretty much everything [cam, heads, pistons, intake,carb etc.] as that motor was the lo perf one with small valve heads.
Pretty easy to get 400hp, and not use nitrous or a blower. Chevy got nearly that with stock Corvettes and some other models. The old 2.02 fueler heads, or a new set of aluminum heads, then a 280 cam (or something similar) a good hi rise aluminum intake and a 780 Holley double pumper, with good flowing equal length tube headers. If it doesn't get 400 hp with a good tune, it will be very close!
400 HP is a majic number. You can build 350-375 HP using stock parts but the 400 mark used to be real hard to reach. If you build it using l-79 pieces you can tune it to 375 HP easily. With a more modern manifold and 2 fours using L-79 pieces lighten your valve train a bit so it can rev and not float you should be able to attain the 400 mark or very close to it. I have always thought that you needed 375 to 400 HP to just be a healthy streeter, I have no idea where I came up with the numbers just a dumb number that came into a young man's head and never left. But I said that to say this, you really can't tell the difference between 375 and 400 HP by the seat of your pants. 400 is a nice number and gives you braggin' rights but if you only squeeze 375 out of it no one at the hot dawg stand will know the difference.
put on a good intake and a holley carb, add a loud exhaust, adjust the carb so it wont idle for shit and lie about whats under the hood like everyone else does.
Sorry, aftermarket splayed caps, I should have mentioned that....just figured it was already a given.
Fulie heads and a 501 cam and domed pistons should get you there plus a big carb.Plan on racing gas only
i had a 327 with a AFB 461 heads 194 intake valves that dynoed at 482 on racing gas but wasn't streetable 8000rpm through the lights so you should be able to get 400hp with the equipment available to-day better heads, intakes, cams, plan what you want and go for it