DucatiDon

So its finally begun....

Quick recap:
I had finally found and picked up a 512 CE block (4.0 bore, 4-bolt main, but with the PCV breather hole like a 327)
Got it off to the machine shop for bore/hone and stroker clearancing.
It cleaned up nicely at .030 over.

This week we ordered a Manley forged crank, 6" forged rods and Icon forged flat top pistons with offset wrist pins. The icons have 4 valev reliefs, so they have alittle more dish than I was counting on (6.4cc). This should drop the compression from 11:1 to 10.8....we shall see.

Once we get everything in, we will measure the deck height and see if we need to take any off.

Ill post pics when everything shows up.

I will be hitting up Straub for a custom cam grind in a few weeks.

66since71

Don, nice start! Im guessing 4 bolt mains also means large main journals? And...how'd you find the block?

Harry

JohnZ

What are you using for heads when you think you're going to have 10.8-11.0 to 1 compression with flat-top pistons?

DucatiDon

Yes, large journal. its essentially a 350 with a breather. I found the block from a forum member. Shipping was expensive.
I'm planning to use AFR 210cc 65cc heads.

I have a 68 Z28 intake that ill use also.

bluester

That must be a '68 SS350 to be lg. journal and have the PCV setup, right?

Tom454

I'm building a stroker as well and using a Z28 intake. What carb are you considering?

65tripleblack

Hi Don,
John Z is correct in post #3. I noticed it earlier but didn't point it out as, knowing you somewhat, I thought that it might have been a typo. Your non-response now has me concerned.

You should ideally be looking for about 8.5:1 DCR if you plan on using 93 PON pump gas. With a very careful build, you can go 8.75:1 or better. Unless you install a very mild cam in your build, I'm afraid that your SCR is much too low!

DucatiDon

Tom, I think Ill try a Quickfuel 750.....


John Z explain....

My calculator has Static at 10.8 and dynamic at 7.79 (with a cam that Comp recommended) ......If I reduce the cam, lower the lobe separation from 110 to 106 and the duration to 280 from 300 i can get the dynamic to 8.8 .... Is there a better way?

I am much less familiar with DCR...... Ill go do some research I guess.... What would y'all recommend?

So with a quick study, it appears that I want the DCR between 7.5 and 8.5......

Modifying the cam can raise the DCR.... A tighter lobe separation angle makes the most difference....So Ill want a cam with 290 duration ground on a 110 separation....... for 8.2. We can play with cam numbers to get the best DCR.... am I missing someting else?

64con

http://www.claysmithcams.com/sbc-377...k-torque-3600/

THis is the cam that chris straub recommended for the 383 stoker with afr heads

DucatiDon

That one gives me an 8.27 DCR

due to the tight intake lobe separation no doubt...

DucatiDon

OK.
Ready for a Cam Recommendation.

Block came in at .040 Bore. Zero Decked to match piston height.

3.75 stroke, 6" rods, pistons 6.4cc reliefs
AFR 210cc heads 65cc chambers

10.9 compression with .039 head gasket

3000lb corvette convertible

RS500 5 speed .65 OD 3.73 gears

6500 rpm limit (7000 max) Street car maybe an occasional drag strip pass on vintage days.

Im seriously considering the Howards 111815-10 237/245 .56/56 on a 110.
Would like to hear what CStraub would suggest....
Ready Go:

Scott Marzahl

With your compression, a .079" deck height seems like youu are,asking for trouble with detonation. I don't think the Howards cams are billet either.

DucatiDon

That didnt read right..... Zero decked .040 bore. fixed.

63mako

Custom Comp cams, Lobe 3196 intake, 13477 exhaust, Steel billet core, pressed on Iron gear. 4 degrees advance ground in, 110 LSA Your AFR heads will need 8019 springs.
Cam specs:
3196 Int. Lobe - Dur. 288, Dur @ .050 236, Dur @ .200 162, Lift W/ 1.5 .585

13477 Ex Lobe - Dur 291, Dur @ .050 237, Dur @ .200 156, Lift W/ 1.5 .566

Comp Cams Custom Grind Part# 12-000-44 Grind # CS 3196/13477 R110

With your parts and specs and this cam, figuring a 4.125 gasket bore I get 10.85 to 1 compression, 8.31 to 1 DCR, Quench .039, intake closing point 70.
If your running @ 500 ft elevation this drops to 10.75 compression @ 8.21 DCR.
Cam operating range 2300-6000, Est peak HP 6000 RPM. Redline 6500 RPM
Duration 288/291
Duration @ .050 236/237
Lift 585/566

Most any cam over 288 with 110 or more duration will work (some better than others). This is what I would put in it. Assuming 1 3/4 full length headers and 2 1/2" exhaust, low restriction mufflers. Will probably run on 91 octane.
This intake fits your heads, What hood do you have?
http://www.summitracing.com/parts/wnd-7530/applications

DucatiDon

For intake I have a 68 Z28 dual plane, as well as the 63 dual plane.
I plan to break it in with the 63 intake and exhaust manifolds, and then upgrade the exhaust and intake down the road...with a quickfuel 750.
Id ;like it to have some amount of manners from idle to 2500...manners, not neccessarily tire shredding power.

cardo0

Good catch on a large journal 4 bolt block with the early breather Don.

Hope u go with a solid roller to match the old style block. A little tappet noise to make the vintage engine sounds also.

DucatiDon

The jury is still out on the suitability of solid rollers for street cars. I dont want to have to build this engine again in my lifetime....

resdoggie

FWIW, here is my build:

355 CI, 10.6:1 SCR, 8.3:1 DCR, B-W M-21, 3.55 rear, 650 Holley DP Street HP, AFR 195's 64 cc, K-B domed pistons w/ .5 cc dome volume, Center Force DFX clutch/PP and billet steel flywheel, Howard's Cams retro HR, .560"/.560", 280* duration, Weiand Team G 7530 SP intake, Stewart Stage II WP, 180* thermostat.

I modified my original HEI to limit mech'l advance from 16* to 12*. My initial was then set at 20* for a total of 32* @ 3000 rpm. My vacuum can is also the original and advances 10* @ 8" giving me 42* overall. I just replaced the main jets to 70's from 68's. Still tweaking the 4150 but I may need to go with 72's. Car runs fine on the street with 91 pump gas.

63mako

The port size on the 2 intakes you have are about 165 cc. They are made to feed 302-327 CI and do that well.
The heads have 210 port size. The 210 CC heads are made to feed a 383 and up small block and do that quite well. Obstructing almost 25% of the intake port on the heads is a waste of a perfectly good 210 head. This will kill bottom end power due to fuel dropping out of suspension in the head port as velocity drops and kill power up top due to the major restriction at the intake.
Manners will be fine. Need full length 1 3/4 headers, 2 1/2 exhaust and free flowing mufflers.
Your building a 500 HP small block and corking up both sides of the engine, intake and exhaust to cut your peak HP down to under 400 HP. Coupled with your wanting High end power and almost 11 to 1 compression then restricting that considerably selecting a cam to provide that you will have an engine that neither performs well at low speed because it is built to go too 6500 redline or performs well at top end because you got it corked up on both ends. Need to reassess what you actually want to do. I am just trying to help you.

mid-year crisis