400sbc build off

Ran my 400sbc with just a rering and reworked 305 heads (ouch) all summer and winter and now for spring ive pulled a fully forged rotating assembly (3.875 stroke, flat tops, h beams, arp hardware) and im getting the block punched .030 for 420 cid.

My buddy bought kb hypers, forged i beams and stock crank, 30 over 400 he is going to run dart eagle platinums i think.

He expects to beat me with 'engine building experiance', what can I do to take advantage of the strength ive got in a forged build, I picked these parts up over the past few months super cheap.For example would a 294 with 3000 stall benifit cause it will spin higher? Will dart iron eagles and a xe284 with a 2400 stall suffice or are they mismatched?

Lastly What kindve power levels am I looking at? camquest says 516 hp with that combo. Will retrofitting a roller setup be worth it, or going to solid rather than hydrulic? This is my first serious biuild, ltos of learn.

I will be porting the heads as much as my little knowledge allows me.

Oh and for the record hes running a white 87 camaro with 700r4 and 2.73's soon to be 3.42s and im running an gold over orange 80 z/28 with a th350 and 3.42s however I may be buying an rear end with 3.73s and LSD. Should be fun


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Get some better heads. Since the 700R4 has a deeper first gear he`ll have a advantage there also. 400`s like heads that breathe and I`m sure the longer stroke crank you`ve installed does also. Get some heads that have at least a 200cc runner.

So I should start scouting out some used ones, budget for heads is under 1000 so should I look for used brodix, trick flow 23 and what else?

305 heads on a 400?
bet she is choking to death.
also a 400 .030 over is 406 cubic inches.
At least that what my 406 was bored to.

He's adding a 3.875" stroke crank, stock 400 has 3.75".
4.155"Bore X 3.875"Stroke for 420.3ci

The 200-215cc Canfields would work nice.>>>>>>>>>>>>>>>
http://www.competitionproducts.com/products.asp?dept=18

Doug Herbert used to have good prices on them also.

Depending on how the heads have been reworked 516 hp might not be realistic. A 420 will need a good sized set of heads. Something like a Dart 215 or bigger. How radical is this build ? Is it a ride around car or are you looking to smoke your buddy ?

Vortec heads are supposed to be awesome

I'd set it on KILL.
Patriot Freedom 225 heads, 2.08"/1.60", flow as follows:
0.100" 82/70
0.200" 158/119
0.300" 222/164
0.400" 259/194
0.500" 287/215
0.550" 296/220
0.600" 298/222
0.650" 299/223
0.700" 301/224
CompCams solid flat tappet camshaft w/1.5 rockers, part #12-515-5, grind #288TLS-6, 288/296, 259/266, 0.550"/0.570", 106/106/106, 80 degrees overlap, timing events @ 0.050" 23.5/55.5/59/27. Installed straight up.
10.5:1 static compression ratio.
850 double pumper on RPM intake.
1 3/4" or 1 7/8" equal-length, long-tube headers.
This DynoSim was calculated through the mufflers.
RPM HP TQ
2000 149 392
2500 193 405
3000 246 431
3500 321 481
4000 397 521
4500 469 547
5000 532 559
5500 564 538
6000 590 515
6500 586 473
7000 567 425
7500 541 379

Tried 14 different cams to get here. Comp calls for a 4800 stall converter with this cam in a 350, but in this big motor, we're making over 430 ft/lbs of torque by 3000, so I wouldn't think you'd need over a 3K converter with the right gear. Would like to hear other's opinion. A Victor Jr. on this motor made 584hp @6500 and 536ft/lbs @5000. A Torquer II made 557hp @6500 and 518ft/lbs @5000. Dart Pro1 230 heads with RPM intake made 557hp @6000 and 539ft/lbs @5000.

L31 Vortecs are a great head, but just a little small for this particular motor, coming in at 490hp @5500 and 504ft/lbs @4500.

Ive read patriots flow numbers are inflated. These can be had for cheapish, that could be a killer combo and would go perfect with my3k stall idea.

I was planning on using performer rpm heads on my 406. Also the rpm cam with 1.6 roller rockers. Do they flow enough or would I need larger than the 170cc? Rpm airgap intake and 750 holley. 10.5:1 cr. Mating to a 4-speed and 4.10 rear.

Smitty, this will be a very nice street motor. Makes 400 ft/lbs @ 1700.
RPM HP TQ
1500 110 384
2000 164 432
2500 208 436
3000 264 462
3500 330 495
4000 387 508
4500 437 511
5000 474 498
5500 483 461
6000 456 399
6500 396 320
Cam is Edelbrock RPM #7102, 0.488"/0.512", 234/244 @ 0.050, timing events @ 0.050 10/44/59/5, 107/117/112.

Deicided trick flow super 23 195s. Gonna port the hell out of them to take advatange of the 400's displcement and deshroud the valves for the bigger bore.

According to dyno2003 itll make 507 horse and 560ish ft lbs. Thats with a magnum 292 and tunnel ram. Ran the optomizations for torque under the curve and it says I need a smaller cam with less overlap so Ill see what I can find because that left it with 570 horse and slightly more torque. In the 'maro that'll run 6.6lbs/hp. The z06 is 6.4 lbs/hp. We'll see who thinks I cant build an engine now.

Ended up picking a set of dart iron eagles for 350$.

This will allow me extra money to put into a nitrous kit just incase.

200cc 72cc chambers. I decided against the 215-230cc runner because weve stopped scrapping over the build off and its more friendly now or would i greatly benefit even on the street from porting a few cc's out of the runners?

Does anyone have any information on specific iron eagle porting techniques, they are a popular head. I did do a search on the forum so I guess im looking for individual experiance here.

Just a friendly bump.

Im so excited about building a big cube small block over the standard 'boring' 350's. Does anyone else stay up untill the wife yells that its 3 int he morning, just staring at parts?