uxojerry

I have a set of AFR 210s left over from an engine upgrade. Superchevy did a modernized DZ302 build a couple of years ago using AFR 210s and the motor did 519hp at 7400 rpm.

My thoughts are to run the AFR 210s through the AFR 220 port program then build a slightly larger short stroke, large bore motor. Im thinking 4.185 bore and 3" stroke or 4.185 bore and 3.25" stroke. My goal would be +-600hp at 7500 rpm. Which bore and stroke would best fit my goals?

I will use a Dart Little M block, high quality forged components, and a valve train good for high rpm.

63mako

4.185 x 3.25, 6.125 rods, Honda journal size, would get you a lightweight rotating assembly with great RPM potential. 358 CI. Nascar style build. With splayed mains, billet caps. APR studs and top quality rotating assembly I could see 8000 RPM+ potential. Use a flat tappet solid cam with a rev kit, lightweight valves, titanium retainers, Beehive springs. 4.56-5.13 rear gearing W/ 6 speed

bluedawg

What would the benefit of a non roller solid be over a roller solid?

63mako

Nascar uses flat tappet and see 9000 RPM. I am a roller guy but the lifters are heavy and require much higher pressure springs especially if your spinning it upwards of 8000 RPM. Those real high RPM, heavy spring rollers seem more prone to lifter failure. A lot of the Drag race and truck pull engines that see upward of 8000 regularly use High dollar, high tech flat tappets with tool steel lifters. If your limiting to 7500 or so and design it right a solid roller might be the way to go. It will have the capability to make better power. Either way a 1400-1600 PPM ZDDP oil would be my choice.

bluedawg

Thanks for elaborating.

bluedawg

Having these left over is cool. Do you think they'll work at 8k rpm.

63mako

Just my opinion. I been wrong before. Might want to limit RPM and go roller. A good dyno sim program and an intended use/RPM breakdown would help. I would go with shaft rockers as well

Phil Zell

Love to hear those 302's spin.

CA-Legal-Vette

I was toying with this idea before but it really didn't work for the use that I normally put the car through. Ended up going with a stroker crank (3.75).

i also had a tough time finding a 3 inch stroke crankshaft. Who makes them? Callies?

uxojerry

Lunati, Crower and several others have the 3" and 3.25" crankshafts.

uxojerry

I have brand new afr 210 eliminator heads that came off my sbc 427. The 427 is getting ported afr 245s.

The questions was 4.185 x 3" crank or 4.185 x 3.25" crank? If I wanted an sbc 421 I would get one.

7t9l82

there is no replacement for displacement. okay , maybe boost.

uxojerry

I am spending big $$$ on a custom chassis C2 and decided to upgrade the motor with AFR 245s with a medium port program, solid roller cam and shaft rockers. The end result should be +-700fwhp. That kind of maxes out the drive train specs as my T56 Magnum is good for about the same.

I have a 68 Coupe rolling body and am figuring what to do with it. I cant afford a second high $$ custom chassis with the best of everything. My thoughts are to build a really fun car. Since I have the AFR 210s and they can be converted to AFR 220s, what could I build with them that would be fun? A high revving small block would fit that category.

AFR 220s have the capacity for 650hp or so. 63mako's idea of an sbc 358 seem's like it may be the way to go. I want the car to have more bark than bite, and generally be a lot of fun to drive. I never said it was smart, lol.

63mako

I totally get what your after. I had a 302 in my vette. It was fun. Gearing and RPM. Short stroke, long rods, light pistons, big cam

cv67

Love rowdy high rpm motors
So you cant putt them at 1500 in OD drinking coffee thats what a C6 is for. Build it

uxojerry

My original plan was to build was to build a C2-HRM, (Hot Rod Mouse) and a C3-HRR, (Hot Rod Rat). Having an extra set of heads has me in a conundrum. It costs about the same to build a high revving rat as it does to build the mouse. The only money Im saving is on the AFR heads.

A high revving rat is appealing also. Going 4.6" bore and 3.75" or 4" stroke would allow for some big valves and heads. The build would eliminate a lot of low end torque, which is hard on the drive train.

Opinions are appreciated.

L88Plus

Build the big bore short stroke rat.
Torque like a 502 and rev like a 302.
Sell the AFR heads, you don't need top of the line race big block race heads that flow 450CFM for what you want, probably won't cost much to upgrade. Lots of race engine shops have heads that were the $hit a few years ago that were traded in when the big bucks guys swapped to the "soup of the day" heads that can be had for half of what the new stuff costs. Heads can handle big springs it takes to rev. 427 steel cranks are still available.
Unlike the 302, you won't want for more power anywhere in the engine's rpm range.

1977L48

it would be hard to find a large journal 283 crank but put one in a 400 block, im not sure what it would do but it sure would zing to the moon.

cv67

Yeah sell me the heads cheap.

uxojerry

Im toying with a 4.6 x 3.76 for a 499, or a 4.6 x 4 for a 532. If I buy a nice set of heads the engine could be easily stroked to a 565. The 532 is probably more practical.