Thread: Best inlet manifold mild 355 with std red heads

Vac advance isnt all that bad.. light throttle input at cruise RPM with a higher timing like 40-45 wont hurt anything but I wouldnt **** around with it on a carby engine.. If you want economy that bad, a multipoint EFi with sequential injection, and timing with individual cylinder correction is what you need all at your fingertips with a laptop..

Originally Posted by GtoGeoff

No listen to EH, he knows much more than Vizard..............

Whens your next seminar EH? Is it free? People pay for Vizard's seminars because I presume they think he knows what he is talking about...& worth the money.

Wake up Geoff,... i'm not calling Vizard out, i just want you to shut me me down with proof, that vacuum advance is better than all mechanical timing.

So far i am not convinced based on what i have tried, over the last 30 odd years.

Originally Posted by EH179

Where are you going to get a 0-1* advance unit from?

Lol yep. Opted out of the advance curve debate altogether and just locked at 28 and called it done!

Hi
Thanks for responding to are there any used manifolds laying about...………




initial
vacuum advance light throttle cruise when fuel molecules are thin and fuel burn is slow . Generally occurs at XX vac signal in top gear between 50kph and 90kph .

Mechanical advance is exactly that, more to do with full throttle acceleration . Set the mech advance curve that way to start .
Plenty of advance as quick as possible without pinging.

Ignition advance curved is designed around compression /fuel type/ combustion chamber design . Lesser impact bore size and going rich on A/F ratios . Rich mixtures wreck cylinder bores by washing them of oil . Fine for a race car but not street .

There are a few ignition curve modules programable by lap top.

Any used Performers about????????????

Originally Posted by paulzig

So, why are other people having the problem of single plane doughiness? If you have peak TQ of 450-500LBS at 4500-5000RPM even with a single plane, do people think its going to plummet to zero at 4000?

Wouldn't runner size dictate torque peak and plenum volume assist rpm limit?
Does no-one make a smaller runner single plane?
Note: I don't carburetor. So educate me.

Originally Posted by Deuce.

Wouldn't runner size dictate torque peak and plenum volume assist rpm limit?
Does no-one make a smaller runner single plane?
Note: I don't carburetor. So educate me.

Yeah but most base units are pretty small no need for smaller still... If you have a runner length of 5 and a port length on the head around 5" that total of 10" is fine for a 355 at 6000-6500, a dual plane whilst having a longer runner which in theory should make more bottom and top RPM ranges like a tunnel ram, it doesnt because its not straight, it takes energy to turn, airspeeds get too high as RPM increases so thats why it helps low end usually.. You could cam the f-ck out of a dual plane engine, and overcarb it if you leave the divider in place, do that to a single plane and you'll have the doughiness problem..

You can set up induction size for 7500RPM+ and cam for 6000 like GM did on LS3, free the induction so its not a restriction then set RPM with valve events... Works on efi, and carb...

^^^^ well said.

EH
Your comments show you know NOTHING about timing an engine & integrating the vac adv curve with the centri curve. Vac adv does NOT destroy engines, as you claim, another example of your ignorance on the subject. If you really knew anything about it you would know that after the switch to the useless PVA, MVA was there in the background as a safety back up, right up until the end of the carb era. The big three used it to prevent engines from overheating. This is the Chrysler system, Ford & GM similar:
"When engine coolant temp at idle reaches 225*F, the TIC valve opens automatically & applies manifold vacuum directly to the dist. ...This increases the engine idle speed & provides additional engine cooling."

Wrong thread....

Originally Posted by GtoGeoff

EH
Your comments show you know NOTHING about timing an engine & integrating the vac adv curve with the centri curve. Vac adv does NOT destroy engines, as you claim, another example of your ignorance on the subject. If you really knew anything about it you would know that after the switch to the useless PVA, MVA was there in the background as a safety back up, right up until the end of the carb era. The big three used it to prevent engines from overheating. This is the Chrysler system, Ford & GM similar:
"When engine coolant temp at idle reaches 225*F, the TIC valve opens automatically & applies manifold vacuum directly to the dist. ...This increases the engine idle speed & provides additional engine cooling."

And you are showing your arrogance by totally disregarding the threads title, which is about inlet manifolds...not MVA.
You keep banging on about mva in a preacher like manner, but nobody really cares!
I have NOT seen anyone else on here support your diatribe on this, yet a few have supported locked timing?

As i said in the correct thread, i am sitting out of the argument, yet here you are preaching again...

HI
Any used performers about??

Quad webers or triple with different length inlet tube do make torque more or less .
Edelbrock not only use manifold runner length but taper as well . All this is used with a corresponding plenum volume for the application .

Smitty,
Happy to comply but numerous others chimed in about vac adv.

Swampy,
Quad Webers/Dellortos do make more torque. D. Vizard's How To Build HP, Vol 2. has a lot of info on Quad W/D carbs. There is a dyno curve of a 427 Ford with Quad 58 IDA Webers that made 702 hp. A 355 with quad 48 IDAs made 'almost 500 street driveable hp'.

From the same book: " Changing from a 750 Holley on an Edel Perf to a Dellorto set up [ Quads ] produced an almost constant 45 ft/lbs increase throughout the rev range on this 350 Chevy,. At the top end this produced a 50 hp increase. Along with increased output came reduced part throttle fuel consumption, a glass smooth 400 rpm idle & sprint car like throttle response."

The Sidedraught Webers also make great #s.

Best place/price to buy Webers is TopEnd Performance in Calif.

Better off with EFi TB than webers, they would be cheaper...