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Search found 1271 matches

by steve cowan
Thu Jun 17, 2021 3:48 pm
Forum: Engine Tech
Topic: 2.00” or 2.02” intake valve in a 351w D0OE head?
Replies: 30
Views: 791

Re: 2.00” or 2.02” intake valve in a 351w D0OE head?

Throat size…something I completely overlooked #-o Throats are 1.80”-1.84”, which with the current 1.94” valves gives 92.7-94.8%. A 2.00” valve after equalizing all the throats at 1.84” gives 92%…a 2.02 gives 91%. A 2” valve is going to be super tight though, putting the edge of the valve right agai...
by steve cowan
Thu Jun 17, 2021 3:44 pm
Forum: Engine Tech
Topic: Short Block "Kit" Opinions Wanted
Replies: 24
Views: 1001

Re: Short Block "Kit" Opinions Wanted

Hi all. I'm no longer in touch with the machine shop that built or assisted in building several of the engines that have gone through our hands over the last 30years or so. That leaves me in a bit of a quandary regarding the approach to another project. This one is a Gen 1 383. I have the heads, hy...
by steve cowan
Wed Jun 16, 2021 12:58 pm
Forum: Engine Tech
Topic: 2.00” or 2.02” intake valve in a 351w D0OE head?
Replies: 30
Views: 791

Re: 2.00” or 2.02” intake valve in a 351w D0OE head?

This may be a lost cause… These D0OE heads that I have a ton of hours in I would really like to use. But, when someone in a past life bowl hogged them, they cut all the bottom angles out. My machinist wouldn’t do the VJ for me…said they would be a complete turd with the 1.94” valves in place. I bel...
by steve cowan
Wed Jun 16, 2021 12:52 pm
Forum: Engine Tech
Topic: Port volume vs flow vs velocity
Replies: 57
Views: 1701

Re: Port volume vs flow vs velocity

Now here’s another question. With the higher port velocity of a small head, is it more beneficial to have a slightly later closing intake valve to take advantage of the higher intake inertia? If I am understanding correctly, this may help from the midrange and up, with less detriment to the low rpm...
by steve cowan
Tue Jun 15, 2021 4:04 pm
Forum: Engine Tech
Topic: Port volume vs flow vs velocity
Replies: 57
Views: 1701

Re: Port volume vs flow vs velocity

Here is an old thread from Larry with a lot of info on this subject. https://www.speed-talk.com/forum/viewtopic.php?f=1&t=840 Larry has put up amazing information over the years,we need to remember application as well rpm etc PRH made a good point about airspeed.I know a couple of guys on this foru...
by steve cowan
Tue Jun 15, 2021 1:51 pm
Forum: Engine Tech
Topic: Port volume vs flow vs velocity
Replies: 57
Views: 1701

Re: Port volume vs flow vs velocity

People have to ask themselves where is there right foot 90% of the time, In a racing application its a different story to some degree but in a 6000 rpm streeter smaller wins in my opinion. There is so much choice in cam lobes,cylinder heads etc compared to before. I think people underestimate a genu...
by steve cowan
Tue Jun 15, 2021 5:46 am
Forum: Engine Tech
Topic: Tunnel rammed 23* 421sbc
Replies: 25
Views: 1439

Re: Tunnel rammed 23* 421sbc

Burns spec’d tri-y headers 1-3/4 10.5” stepped to 1-7/8 10.5” primaries into 2-1/8 secondaries for 10.5” with 2-3/8 choke into a 4” single tailpipe or 3” twin pipes. I really liked the fat mid range of the single pipe on the last engine.... but im thinkin i may go regulat twin pipes this time, i th...
by steve cowan
Tue Jun 15, 2021 5:30 am
Forum: Engine Tech
Topic: Port volume vs flow vs velocity
Replies: 57
Views: 1701

Re: Port volume vs flow vs velocity

I’m trying to better understand the relationship between the items in the subject line and the overall effect on power output and rpm range. This is related more to street performance builds rather than racing applications although I’m sure there is some crossover there. On a small port OEM head, i...
by steve cowan
Wed Jun 09, 2021 9:43 pm
Forum: Engine Tech
Topic: 243 LS SSR...Stumped.
Replies: 32
Views: 1761

Re: 243 LS SSR...Stumped.

PRH wrote: Wed Jun 09, 2021 6:10 pm Still sounds to me like what TK was suggesting and what DT was instructing are fundamentally the same thing.
A9BD8EF5-70A3-4956-9DCE-32EB0675CF2E.png
Just to keep you happy -
Let's just say you are fundamentally correct as always.
:lol:
by steve cowan
Wed Jun 09, 2021 2:48 am
Forum: Engine Tech
Topic: 243 LS SSR...Stumped.
Replies: 32
Views: 1761

Re: 243 LS SSR...Stumped.

20210609_164116.jpg
20210609_163941.jpg
20210609_163844.jpg
20210609_163543.jpg
I was fortunate enough that Don sent me all this plus more back in 2011.
by steve cowan
Tue Jun 08, 2021 7:50 pm
Forum: Engine Tech
Topic: 243 LS SSR...Stumped.
Replies: 32
Views: 1761

Re: 243 LS SSR...Stumped.

My take on riblets are small channels, my interpretation is what I described, hopefully TK can confirm as I could be wrong....
A picture is worth a thousand words.
by steve cowan
Tue Jun 08, 2021 1:31 pm
Forum: Engine Tech
Topic: 243 LS SSR...Stumped.
Replies: 32
Views: 1761

Re: 243 LS SSR...Stumped.

What Tony is describing is NOT the riblet,
It's basically smoothing the apex in the direction of flow.
Speeds are fast and boundary layer thin and fuel is trying to turn.
It's not a cfm gain,more helping with stability.
It's a cool speed secret.
by steve cowan
Sat Jun 05, 2021 4:55 pm
Forum: Engine Tech
Topic: 193 Swirl Port Porting Question
Replies: 24
Views: 1012

Re: 193 Swirl Port Porting Question

Intake valve diameter is 1.94”. Is 90% a better ratio of throat diameter to valve diameter? I’ve seen numbers ranging from 86-89%. Cleaning up the throat to the 90 deg step gets it to 87%. I don’t want to invest much into these heads. Just some bowl/throat cleanup and lap the valves. Figured since ...
by steve cowan
Sat Jun 05, 2021 3:57 am
Forum: Engine Tech
Topic: 193 Swirl Port Porting Question
Replies: 24
Views: 1012

Re: 193 Swirl Port Porting Question

I’m doing a low $$$ 307 Chevy build with leftover parts and I have a low mile set of 193 swirl port heads that are the best heads I can come up with without spending any $$$. Engine is going into a rat rod 46 Chevy so it’s just something to have fun with. Cam is a small solid cam 224/224 @ .050” on...
by steve cowan
Wed Jun 02, 2021 3:56 pm
Forum: Engine Tech
Topic: Pump gas 421 SBC HP
Replies: 40
Views: 2316

Re: Pump gas 421 SBC HP

mt-engines wrote: Wed Jun 02, 2021 3:00 pm1st pull
Hey MT,
What carb were you using on the first pull,interesting how little fuel used initially.