The results should be interesting.

 

Yes...

 

You don't think the 220s are a bit much for a naturally aspirated street car?

-- Joe

 

No, not with the velocity those heads have and the huge cubes. 195's on a 355 are same as a 220 on a 421 imo

 

I guess. I'm running 210s on my 412 and it seems ok but I wouldn't go with a smaller cam or bigger heads.

-- Joe

 

Yeah a good 210 can feed a 400-415 motor to 6000-6500. Comfortable rpm range for a street strip fun build. 421 with more stroke can take another 10cc's for same rpm range.

Depends on what you are trying to accomplish. Big power numbers from high ve motors needs big airflow and you get that with more port area, or less valve angle for more velocity. Standard sbc heads are limited in velocity due to port shape. So have to go bigger. 1989gtatransam runs very well with ported afr's that produce 222cc's and he is only 369 cubes but going to 6800 rpm

 

I like 210s on 350s, they run great.

 

I dont think so. The stock LT4 back in 1996 came with 195 cc heads from the factory. 71 more cubes and 25 cc's really isnt crazy is it??

 

If I can rev to 6400 or so I will be happy!!!

 

Running 230s on a 383..while its strong at WOT and upper ranges I think they are too big overall. Car would feel snappier everywhere with a smaller head if that helps. Engine doesnt come alive til about 4k

 

Doesnt help!

 

185, but sure close enough. It depends on what the velocity is at low RPM operation. You don't want the car to be a stone under 3k, even if it makes 700 horsepower at 6500..

What is the port size on those? What intake you plan on running?


-- Joe

 

What size cam are you running?

 

I'm curious to see how much the head swap will make a difference. I just finished a similar build. I wonder if our numbers will be similar.

427 SBC
AFR 220 Heads (65cc)
242/248. .576/.600. 112LSA
HSR Intake
10:5:1 Compression

 

I hear what you are saying but they were 195's......

Miniram and i think they pour 222cc.

 

Pm sent

 

I dont see a reason to be wot under 3000 rpm, so car should never have to worry about low end. 421 cubes makes alot of torque with that long stroke. It doesnt take much power to move an fbody or vette. Stock L98's did a good job of that with not that much torque.

I will be tuning my car all motor this year, bypassing turbos as i break in the new rings. 245cc heads on a 9 to 1 comp 400" motor. 246 deg cam. Previous driving experience was good. Car felt just as alive as the 195cc afr's and baby 233 deg cam. In fact i think it was abit more peppy although it did not load the converter as hard so some torque was lost there, it still was more than enough to make car fun. Also i changed turbo housings which delayed turbo spool so that may be why the combo didnt load converter quite as hard. Either way i dont expect issues. Results should be interesting.

230's are too large for a 383 unless you are doing 7500 rpm+. Naturally it wont be as snappy unless real high compression.

 

I'd ditch the miniram and get a singleplane port matched. The miniram won't support the CFM you need.

Is Jim doing this build for you?

-- Joe

 

miniram has been worked over a touch plus i like the runner length. jim is playing a big part yes as he built the stroker....

 

I ran a miniram for a little while on the Corvette back in 2007 or 2008.

Any horizontal draw intake is going to have restrictions vs a direct draw singleplane.

-- Joe

 

I am running measured 222cc heads on my 369cubic inch motor. I can say the motor is very snappy and takes right off from a stop even with a stock torque converter. No problem lighting off the tires. IMHO he should have no problem with 220cc heads on a 421CI motor. If it were mine I would have went with 235cc heads providing the intake gaskets would seal up.

 

11.5:1
260/268@050
294/302
108 las
640 lift
Solid roller

Needs over 700 lift to take advantage of the heads on now just not willing to on a street car not worth the valve guide wear to me. Gentle lobe shouldnt beat up parts

Nothings perfect eh?

 

I'd like to play with that cam on one of those programs but somthing is telling me you may have a bit to much duration for your cubes.
Shorting the duration up will wake it up down lower in the rpm range.
In allmost every combo I've seen tested, over caming is worse than over heading a motor.
I like huge cubes, heads, cams and rpm tho You prolly have quite the spinner!!

 

My buddy runs less cam, about 248-250 deg on a 406 with a hell of a 208cc head and goes 10.4's at 132 all motor . There are ways to skin a cat, but his motor is about done by 6300. Short rpm range but tons of power in there

 

TTOp if youre up for doing a sim I can send you the cam specs that matter.
It has acceptable torque for most driving.
With the gear tire dia and 6 speed its at 3k or more right now just normal driving dont want to blow the tires off it. So by the time I stab it im around 4k +- and the party starts. At 5k it feels like someone rearended you lol.
Plan on running it to 7, 7200 tops at the track.
Its pretty fresh so only ran it up to 6800 so far pulls awfully hard up top.

I wont hijack anymore back to Ricky

 

88Black Z-51, I'm just wondering, are these numbers thru the Bosch MAF and factory air filter box?

 

Not sure but i thought he was tuning through a FAST classic system. I could be wrong

 

Yeah, for some reason I think your correct. I just couldnt find the info real quick.

 

Yes you are correct. It was thru 1 3/4 hookers with 3 inch duals as well with a reasonator that flows like crap.

The tune wasnt bang on, but it was close.....The tq curve was very flat. IIRC 440 rwtq at 2500.

 

IROCThe5.7l,did you port the HSR for your 427 build and how well does it match up to the afr220 heads?Are the 220's street port or comp port?Should be a strong runner,with a nice power curve...

 

Would also be interested on how the mini-ram matches up to the afr220's for Ricks 421 as well...would love to build a big cube sbc down the road,but I want to keep the stock hood on my 88T/A...so I'm really interested in these big cube motors with HSR or MR intakes....

 

Both 1206 so should be good.....

 

I had to put a lil thicker intake gasket on my build to get the intake ports to line up just right..

 

http://forums.corvetteforum.com/c4-t...a-chapter.html

 

Sad. Very eager to see the results of the 220 heads and raise peoples eyebrows to the notion that big motors need more head. Keep us informed of the new owners results

I didnt read the whole thread but why part car out? Couldnt sell whole?

 

Oh wow that is big news, though I can't blame you for doing it. The LS platform is super tempting and going with a Z06 is hard to beat! Good luck with the new project

 

always liked the big small blocks

 

Saw some dyno tests recently comparing the bigger heads to 180s on a 383. I almost pooped myself. The 180s had 10 more foot lbs and lost only 4hp.

Almost made me wanna smack myself for ditching the 195s and buying the 210s.

-- Joe

 

I shoulda bought a C6 when I sold the C4.. Nice clean cars. I'd keep it stock though.

-- Joe

 

Using what parts I had
Main useage is for WOT/strip
car has plenty of gear goes through it quick so low end tq was never a concern
Focus is on 1/4 mi time more than street use. I dont lug it or worry about mpg lol

Sure an AFR 210/220 would pick things up overall. 210 comp probably perfect size but dont want to blow the tires off it, want it pulling hard past 7k or to it at least

See how money looks in the next 6 mos. Cost plus another set of shaft rockers adds up.

Nobody seems to want to buy these Darts and getting stupid offers on the Jesels as they wont fit the AFRs. so...

 

Do you have any more detailed info on this? Those are very interesting results indeed.

 

Sorry boys!!!