408 Build

[mopowers]

I don't put faith in that quench recommendation... it's like quench will solve all your detonation issues.

I've got about that same quench with 9.7:1 and it's on the edge of pinging with 91 california pump gas.

Well, why didn't you mention something in my thread then?

What heads do you have any what dynamic compression are you at?

I'm right at 9.7:1 with my iron head 340 with great quench (.036") and have no problem running 91 octane. I'm hoping with aluminum heads and just slightly higher DCR )though the SCR is 10.4:1), I'll okay on my 408. Time will tell.

 

[crackedback]

It’s hard to find good parts sources in Canada sometimes, I was thinking of getting a new hole shot or TCI converter, you thinking something built instead?

No to both of those choices. TCI is known as Total Crap Inside.

TCS is in Canada somewhere. Ask around with some of the drag race guys local to you.

You want it to move out? Get a converter built that flashes to 3500ish and is tight on cruise. A good converter company can set that up and it will be a good running piece.

 

[autoxcuda]

I’m using a M1 Dual plane with an 800cfm Edelbrock for street.

I think a edelbrock RPM might be a better fit. The M1 dual plane is like a stock replacement in aluminum.

 

[autoxcuda]

Well, why didn't you mention something in my thread then?

What heads do you have any what dynamic compression are you at?

I'm right at 9.7:1 with my iron head 340 with great quench (.036") and have no problem running 91 octane. I'm hoping with aluminum heads and just slightly higher DCR )though the SCR is 10.4:1), I'll okay on my 408. Time will tell.

Edelbrock street ported.

DCR of 7.92:1 I found on a old thread

 

[jbc426]

Don't waste your money on a cheap or even mid-priced converter like that. Grab a custom torque converter from Precision of New Hampton or other reputable place, and give them all the information about your specific application once you sort it out.

For your final cam specs, I'd order one spec'd by Dwayne Porter before I would guess myself. His recommendation is going to be as close as your going to get to perfection, but then I would send him the heads for porting and a proper valve job too.

 

[mopowers]

Edelbrock street ported.

DCR of 7.92:1 I found on a old thread

So, you're at 9.7:1 SCR, with 7.92:1 DCR? What cam are you using? Also, what's the quench distance?

 

[autoxcuda]

So, you're at 9.7:1 SCR, with 7.92:1 DCR? What cam are you using? Also, what's the quench distance?

My quench distance is .034. pistons .002 out of hole.

Mine is 4.07 bore. 30 over 340 block.

 

[mopowers]

View attachment 1716450452

Thanks. Hopefully mine runs okay with the tight quench. I remember the experts here saying I'm better off with slightly higher compression and tight quench vs low compression and larger quench distance (in terms of detonation resistance).

 

[Bewy]

Beats me why people keep using DCR as a guide to what octane fuel their engine can use. Missing from the DCR calculation are important factors will affect the final number.

 

[furrystump]

I would definitely get a custom converter. I have been happy with PTC. Give them all you specs.

 

[65rbdodge]

Not me but a friend of mine broke a 273 rocker arm on a 528 solid cam. I personally wouldn't use them with some stiff springs

 

[273]

Beats me why people keep using DCR as a guide to what octane fuel their engine can use. Missing from the DCR calculation are important factors will affect the final number.

What should they use or go about it instead ?