New SBC heads

General engine tech -- Drag Racing to Circle Track

Moderator: Team

steve cowan
Guru
Guru
Posts: 2253
Joined: Wed Jul 27, 2011 5:22 am
Location: brisbane AUSTRALIA

Re: New SBC heads

Post by steve cowan »

Bob Hollinshead wrote: Fri Aug 05, 2022 12:29 am
steve cowan wrote: Thu Aug 04, 2022 11:02 pm
1980RS wrote: Thu Aug 04, 2022 8:38 pm

I am going to use my Ported 2925 S/V on these heads since it's ported to the 1206 gaskets and the new heads are about that height in the opening. I have to tell you the pinch when I checked them against my Dart 200s were a 1/4" smaller. Anyone see a problem with that? otherwise everything is almost identical to the Dart heads.

The new aluminum heads bare came in at 20 lbs.
The cast iron Darts came in at 50 lbs.

So 60 lbs. of the front of the car and another 30 lbs. off with the new aluminum radiator deal, close to 100 lbs.
I calculated using a mach index of 690 ft/ sec for your cubes at 7000 rpm a minimum csa of 2.35in2 factors in radius,
Not sure if you can get area without blowing the pinch out.
Otherwise all you can do is make it as big as possible.
Steve, what minimum CSA do you calculate for 377 at 7K rpm? Are you using a version of pipemax? I have a pair of these I'll be playing with soon hopefully, the first thing I noticed when I took them out of the packaging was how tight it was at the pushrod pinch. Planning on 2.08/1.60 valve.
Bob,
Not sure what bore size you are using so here is the equation, be mindful it's a starting point and not set in stone.
Bore2 x stroke x rpm x 0.00356/ 690 = MIN CSA.
using my 383 as an example-
4.030 x 4.030 x 3.75 x 6600 x 0.00356 = 1418/690 = 2.05" min .
steve c
"Pretty don't make power"
EDC
Expert
Expert
Posts: 506
Joined: Wed Dec 29, 2004 7:33 pm
Location: in your mind's eye
Contact:

Re: New SBC heads

Post by EDC »

Bob Hollinshead wrote: Fri Aug 05, 2022 12:37 am
EDC wrote: Thu Aug 04, 2022 3:50 pm Which "brand" did you end up with?

Did a few of the AFR versions and they seemed like a pretty nice casting.

This set build for a "street" solid roller combination in a tri-five Chevy gasser deal.
Image
EDC those springs look small for a solid roller? what are they and how big is the cam?
After lash, a tick under .600" lift. This is a set of PAC Racing 1222X springs and tool steel retainers.
"Quality" is like buying oats. You can pay a fair price for it and get some good quality oats,
or you can get it a hell of a lot cheaper, when it's already been through the horse.

Nil Satis Nisi Optimum

Ed Curtis - www.FlowTechInduction.com
1980RS
Guru
Guru
Posts: 1636
Joined: Thu Oct 13, 2016 10:03 am
Location:

Re: New SBC heads

Post by 1980RS »

F-BIRD'88 wrote: Fri Aug 05, 2022 2:00 am
1980RS wrote: Fri Aug 05, 2022 12:46 am The Dart copies were a little over 1/8" width smaller than the Dart 200's I have. Quite a difference.
With the as cast meat at the pinch you have the capacity to now create the size and SHAPE of the radius of the pinch, as you port these heads for power.
Keep us informed as you do the workup on these heads.
I sure will do that.
1980RS
Guru
Guru
Posts: 1636
Joined: Thu Oct 13, 2016 10:03 am
Location:

Re: New SBC heads

Post by 1980RS »

Since the L-29 is ready to go in the car I decided to start porting these heads in the intake pinch area. The cutters work real well and it seem like the aluminum these are made of are way better than the procomp stuff as they made the cutters all gum up. Will post some pictures as I go along on this. Hope these work well on my next 355 project.
skinny z
HotPass
HotPass
Posts: 2642
Joined: Tue Mar 11, 2008 8:42 am
Location: AB. CA.

Re: New SBC heads

Post by skinny z »

steve cowan wrote: Fri Aug 05, 2022 2:16 am Not sure what bore size you are using so here is the equation, be mindful it's a starting point and not set in stone.
Bore2 x stroke x rpm x 0.00356/ 690 = MIN CSA.
using my 383 as an example-
4.030 x 4.030 x 3.75 x 6600 x 0.00356 = 1418/690 = 2.05" min .
So, as a "starting point", this next engine will be a 4.04 x 3.48 (357) and targeting peak HP RPM at 6250.
((4.04^2)(3.48)(6250)(.00356))/690 = 1.84.
Hmm. I may be there already.
Thanks for a jumping off point Steve.
Good luck with yours 1980RS.
Kevin
F-BIRD'88
Guru
Guru
Posts: 9802
Joined: Tue Mar 27, 2007 6:56 pm
Location: Ontario, Canada

Re: New SBC heads

Post by F-BIRD'88 »

Why only a peak horsepower point parameter of only 6250 rpm from a 355 sbc? I thought you wanted to go fast.
1980RS
Guru
Guru
Posts: 1636
Joined: Thu Oct 13, 2016 10:03 am
Location:

Re: New SBC heads

Post by 1980RS »

skinny z wrote: Thu Aug 25, 2022 3:46 pm
steve cowan wrote: Fri Aug 05, 2022 2:16 am Not sure what bore size you are using so here is the equation, be mindful it's a starting point and not set in stone.
Bore2 x stroke x rpm x 0.00356/ 690 = MIN CSA.
using my 383 as an example-
4.030 x 4.030 x 3.75 x 6600 x 0.00356 = 1418/690 = 2.05" min .
So, as a "starting point", this next engine will be a 4.04 x 3.48 (357) and targeting peak HP RPM at 6250.
((4.04^2)(3.48)(6250)(.00356))/690 = 1.84.
Hmm. I may be there already.
Thanks for a jumping off point Steve.
Good luck with yours 1980RS.
Thanks. I went through one port wall trying to get these heads to be the same opening pinch as my Dart 200's. Guess I got a little greedy, but that's what epoxy's for. :lol:
steve cowan
Guru
Guru
Posts: 2253
Joined: Wed Jul 27, 2011 5:22 am
Location: brisbane AUSTRALIA

Re: New SBC heads

Post by steve cowan »

1980RS wrote: Thu Aug 25, 2022 9:38 pm
skinny z wrote: Thu Aug 25, 2022 3:46 pm
steve cowan wrote: Fri Aug 05, 2022 2:16 am Not sure what bore size you are using so here is the equation, be mindful it's a starting point and not set in stone.
Bore2 x stroke x rpm x 0.00356/ 690 = MIN CSA.
using my 383 as an example-
4.030 x 4.030 x 3.75 x 6600 x 0.00356 = 1418/690 = 2.05" min .
So, as a "starting point", this next engine will be a 4.04 x 3.48 (357) and targeting peak HP RPM at 6250.
((4.04^2)(3.48)(6250)(.00356))/690 = 1.84.
Hmm. I may be there already.
Thanks for a jumping off point Steve.
Good luck with yours 1980RS.
Thanks. I went through one port wall trying to get these heads to be the same opening pinch as my Dart 200's. Guess I got a little greedy, but that's what epoxy's for. :lol:
20220528_161702.jpg
20220528_161344.jpg
Bob,
You need to make E tool like this to check pinch.
You do not have the required permissions to view the files attached to this post.
steve c
"Pretty don't make power"
steve cowan
Guru
Guru
Posts: 2253
Joined: Wed Jul 27, 2011 5:22 am
Location: brisbane AUSTRALIA

Re: New SBC heads

Post by steve cowan »

skinny z wrote: Thu Aug 25, 2022 3:46 pm
steve cowan wrote: Fri Aug 05, 2022 2:16 am Not sure what bore size you are using so here is the equation, be mindful it's a starting point and not set in stone.
Bore2 x stroke x rpm x 0.00356/ 690 = MIN CSA.
using my 383 as an example-
4.030 x 4.030 x 3.75 x 6600 x 0.00356 = 1418/690 = 2.05" min .
So, as a "starting point", this next engine will be a 4.04 x 3.48 (357) and targeting peak HP RPM at 6250.
((4.04^2)(3.48)(6250)(.00356))/690 = 1.84.
Hmm. I may be there already.
Thanks for a jumping off point Steve.
Good luck with yours 1980RS.
It's a starting point for sure,then with a 2.02" intake valve and throat around 89% you have a area of aprox 2.5" at the throat as a reference then start working in between.
My opinion is the pinch does not completely dictate rpm limit,I think it is how well you can turn the fuel and air over the short side and speed past the valve and throat, this is why I believe cfm/ in2 at the throat is important.
steve c
"Pretty don't make power"
1980RS
Guru
Guru
Posts: 1636
Joined: Thu Oct 13, 2016 10:03 am
Location:

Re: New SBC heads

Post by 1980RS »

steve cowan wrote: Thu Aug 25, 2022 10:39 pm
1980RS wrote: Thu Aug 25, 2022 9:38 pm
skinny z wrote: Thu Aug 25, 2022 3:46 pm

So, as a "starting point", this next engine will be a 4.04 x 3.48 (357) and targeting peak HP RPM at 6250.
((4.04^2)(3.48)(6250)(.00356))/690 = 1.84.
Hmm. I may be there already.
Thanks for a jumping off point Steve.
Good luck with yours 1980RS.
Thanks. I went through one port wall trying to get these heads to be the same opening pinch as my Dart 200's. Guess I got a little greedy, but that's what epoxy's for. :lol:
20220528_161702.jpg20220528_161344.jpg
Bob,
You need to make E tool like this to check pinch.
That's pretty cool, thanks.
Elroy
Pro
Pro
Posts: 288
Joined: Tue Jul 16, 2019 12:46 pm
Location:

Re: New SBC heads

Post by Elroy »

1980RS wrote: Thu Aug 25, 2022 9:38 pm
skinny z wrote: Thu Aug 25, 2022 3:46 pm
steve cowan wrote: Fri Aug 05, 2022 2:16 am Not sure what bore size you are using so here is the equation, be mindful it's a starting point and not set in stone.
Bore2 x stroke x rpm x 0.00356/ 690 = MIN CSA.
using my 383 as an example-
4.030 x 4.030 x 3.75 x 6600 x 0.00356 = 1418/690 = 2.05" min .
So, as a "starting point", this next engine will be a 4.04 x 3.48 (357) and targeting peak HP RPM at 6250.
((4.04^2)(3.48)(6250)(.00356))/690 = 1.84.
Hmm. I may be there already.
Thanks for a jumping off point Steve.
Good luck with yours 1980RS.
Thanks. I went through one port wall trying to get these heads to be the same opening pinch as my Dart 200's. Guess I got a little greedy, but that's what epoxy's for. :lol:
How wide is it through there now?
SpeierRacingHeads
Vendor
Posts: 937
Joined: Sun May 13, 2012 1:28 pm
Location: KS
Contact:

Re: New SBC heads

Post by SpeierRacingHeads »

There for awhile early last year I was getting some of these castings that had sintered copper seats in them.

But, I all but got out of the import casting selling.

Never had any issues, probably CNC'd 150 sets of them since 2008.
You do not have the required permissions to view the files attached to this post.
Speier Racing Heads
Chad Speier
785-623-0963
skinny z
HotPass
HotPass
Posts: 2642
Joined: Tue Mar 11, 2008 8:42 am
Location: AB. CA.

Re: New SBC heads

Post by skinny z »

F-BIRD'88 wrote: Thu Aug 25, 2022 8:33 pm Why only a peak horsepower point parameter of only 6250 rpm from a 355 sbc? I thought you wanted to go fast.
That is one engine of a couple I'm contemplating. The end result will largely be dictated by the cam.
What I have to decide is how fast do I want to go vs how far.
6250 is kind of in the middle.

I don't intend to modify the heads I have as the porting done on them is untested because the torque converter let go soon after they were put on. Shortly after that repair, I lost a roller lifter and carnage ensued. So, the task ahead is to measure the heads and decide what they're capable of. The cam will follow.
If the heads support bigger numbers, I may dial it up a little. They're only 255@.500" but other than the flow bench, they haven't been sized up. I'm not certain of the volume or the MCSA. Although they started as a 170cc intake with 64cc chambers.
I've got the winter to figure it out.
Kevin
1980RS
Guru
Guru
Posts: 1636
Joined: Thu Oct 13, 2016 10:03 am
Location:

Re: New SBC heads

Post by 1980RS »

SpeierRacingHeads wrote: Fri Aug 26, 2022 10:48 am There for awhile early last year I was getting some of these castings that had sintered copper seats in them.

But, I all but got out of the import casting selling.

Never had any issues, probably CNC'd 150 sets of them since 2008.
Chad, that work's so nice I wouldn't want to to run them on engine, they look like jewelry. I would just take them to a car show and show'em off, as always great work.
1980RS
Guru
Guru
Posts: 1636
Joined: Thu Oct 13, 2016 10:03 am
Location:

Re: New SBC heads

Post by 1980RS »

Here's what I did today, nothing that looks like Chads work :lol: but we gotta start someplace. Don't laugh, I got 5 1/2 hours in this head. Another question for you guys since I punched a hole in the pinch area. How much time for Splash Zone to setup? This is the 1st time using it, seems a lot less runny than others told me it was.
You do not have the required permissions to view the files attached to this post.
Post Reply