A good 300 whp will easily be mid 12's all day long. 300whp is just about cam/intake L98 range. A basic fresh L98 bottom end with vortec heads, LT4 hotcam and vortec manifold with any 600-750 cfm carb will be plenty

Could I just get the stock heads machined to work fine for now?

So could a stock 700R4 handle 300-350 rwhp?

So if I just get a 350 block, clean it out good and replace what needs to be replaced, machine it into a 383 stroker, use a 400 crank, decent flat tappet cam, KB forged pistons(for later expansion and I really like them for the price), machine the stock heads to flow better, get an edelbrock intake, a holley carb, good air cleaner, 700R4 with shift kit, and a couple extra bolt ons here and there could I get into low 12's?

you dont machine a 350 into a 383, you just bore it. A 383 is a 350 block bored .030 over with a crank of stroke 3.750 either 5.7 or 6" rods and 383 pistons.

since you mentioned "for later expansion" it sounds like maybe in the future you will want more power sooo dont go with a 400 crank, scat and eagle both have some great 383 rotating assemblies for under 800bux.

12s isnt that hard to break into. some gears, good suspension some sticky tires and some laughing gas and there you go

lol ya I am not sure why i said machined...anyway ill got it bored

ya i might do that or I might cheap out and do hypertectic pistons(or stock) and forget setting up for later expansion

will the stock heads be ok?

will stock 700R4 hold up?

If youre dead set on carbed; personally I realize the edelbrock design is harder to extract every ounce of power out of, but I think they make better STREET carbs. I also prefer electric chokes and vac secondaries. (if you plan on running AC make sure you get the little AC idle compensator thing for the carb; I always laughed at em till dad put one on my uncles nova...the AC didnt lug the motor to the ground in traffic)

dont sweat that 2bolt 4 bolt stuff. Factory 4 bolts arent THAT much stronger than 2 bolts. Throw some ARP rodbolts are your reconditioned rods. if its a roller cam, Comp has a pretty awesome XFI cam that theyre very VERY proud of. I cant remember what ithe P/N is off the top of my head though. As an old flat tappet guy, I loves me some 268H with some healthy heads. Its hard to find new performance heads for 350s these days. Everything has 200cc runners, which I dont think you'll need. Make your car light, and put 3.55s in the back.

300whp is performer rpm airgap territory and a 650cfm carb (thunder AVS is a good edelbrock carb). 1 3/4s headers, performance HEI, 8mm wires and 10-10.25:1 SCR. If it was me, I like the iron eagles from dart or the IK 180s (decent aluminum heads) with a windage tray or crank scraper.
You also should avoid high volume oil pumps. its pointless to roar through 5qts of oil in your pan and beat it into whipped cream. get the higher quality MV55 melling pump, make sure you take the cover off and hose out the machining crap between the gears and pack some assembly lube around the gears so theyre not running dry.

For a cam, call comp and have them reccomend an XFI shelf grind once you pick your heads

Aluminum heads dont flow better than iron heads. They disapate head better and are lighter.

Any way im currently building a 383. (my first motor build im only 20)
Im using
Forged 383 stroker motor 11:1 compression
1972 4 bolt main block + machining
New Eagle cast crank
New scat 5.7 forged rods.
new srp forged dome pistons part number- 140344
SCE titan copper self sealing headgaskets 4.060 bore with .62 thickness to get the 11:1 compression with my heads/pistons combo
Dart Iron Eagle 200 cc 72cc heads with 2.02 1.94 valves 5 angle valve job
edelbrock performer rpm intake manifold
rebuilt with choke horn milled off Holley 4 barrel vaccum secondary carb
New Delco remy HEI dist
New high volume high flow oil pump (50)
7 qt 383 oil pan
moroso tall valve covers
New magnum 1.6 roller tip rockers
New comp nitrous 284h cam
New comp lifters
New comp double roller timing chain set
Chrome timing cover and water neck
Spark plug wire seperators
New 400 flex plate
New 383 balancer
Alt relocation brackets
Hedman Long tube headers
Poly motor mounts
180 t*stat
All felpro gaskets including one piece oil pan gasket
Locking header bolts
8.5mm wires

Thats just the motor parts off the top of my head

I honestly have no idea how much power this motor will put down but I hope with the right supporting mods to break into the 11's all motor.

700r4 will handle 300 hp but probally not for that long if you beat on it and it def wont let you utilize every ounce of power unless its a nice rebuilt raptor or similar 700r4(I plan on getting one of those soon)

You need a bigger stall with the new setup(depends on your basic rpm range tho easiest way is to find what cam ur using and get a stall off that)

and you DO machine a old stock block into a 383 what are you dumb?
You can just bore it .30 over and slap a 400 crank in their!
You have to take it to a MACHINE SHOP and have the deck cut, as well as honed for the stroker crank or 400 crank same difference, you even have to grind down areas at the bottem of the cyl walls where the bolts on the new crank might hit! <- thats all machine shop work.

Dont cheap out if your building a 383. Get a good aftermarket 383 rotating assembly from one of the name brands and get forged pistons for the extra money. Any aftermarket dual plane intake, holley 650-750 depending on how extreme you get, a nice cam comp makes some good ones try to search for parts on summit. Notice things like cams and intake manifolds both have basic rpm range in their specs on summit, try to look into similar rpm ranges for the cam and manifold your looking to get. Long tubes are a def good power maker and while ur at it get new motor mounts and tranny mounts, a stall converter and shift kit. Then you have to think about the rear end after that.

First I am totally aware of the machine shop work I am not sure where you missed that part(must have been when I was talking about the heads)

Second Long tubes would be nice but for my street car they don't give me good ground clearance so hello shortys

you dont machine a 350 into a 383, you just bore it. A 383 is a 350 block bored .030 over with a crank of stroke 3.750 either 5.7 or 6" rods and 383 pistons.

That was from another member not you thats what i was referring to when I mentioned the machining stuff.

Second their are alot of guys running log tubes with good ground clereance actually but it is just easier to run shorties so I dont blame you, its hard to find a good exhaust guy anywhere these days any way.
Good luck with your build man TAKE LOTS OF PICTURES and post them for us