Thought I'd get a crack at it this w/end but time is dissapering fast, so here's the mod details for you to try if you get the time....
1/ cant do this mod with the "snorkel" setup ..... must use the "bell" adaptor that goes between the mixer and the carby.... as seen in the first pic.
2/ you'll need a throttle body off of a carby that fits the manifold ( with or without an addaptor) so we end up with tha butterflys bolted to the manifold .... doesnt matter if its Holley or Rochester throttle body but the Rochester will give slightly better ecconomy under normal use over the Holley...... left hand right shoulder the top half of the carby
3/ the hard/easy bit....
All we do is put the "bell" directly onto the throttle body and attach it so there's no airleaks. I had for experimentel reasons intended to just use Urathane for a trial run and then machine up a permanate solution if it worked.
Sounds simple enough hey !!!
The gas carby setup is almost exactly the same in principle but the "throat" is where the restriction lies and its this restriction that causes the horsepower loss. The restriction in the petrol carby is worse because of the small venturies..... so basically the gas carby is a "petrol carby" but without the small venturies, the restriction is still there but is smaller thus the improved HP over the petrol carby.
By removing ALL throats & venturies the HP increase is dramatic as is the ecconomy, the mixer is not inhibbited in any way, lets face it ... we dont need anything between the mixer and the butterflys except an adaptor to join the two pieces together.
The mixer in this setup could be an Impco series 1&2 and will handle a 350 / 400 chev without any dramas. this is because its largely the restriction of the throats and venturies that decreases the series 1&2 performance.
The Impco series 45 & 70 is the recemended mixer for 350 / 400 chevs but its the chosen unit because of 2 reasons.... 1 to overcome the restriction and secondly for high reving motors ( IE: 5000 rpm )
As for the inlet manifold it's self ( and I dont know what type youre running) , the singleplane manifold apparently works slightly better with this setup but either single or duel plane manifolds work well.
I'm running the stock castiron manifold at the moment and rochester carby...... I hope that I can use the rochestor butterflys directly onto the manifold and then place a spreadbore to squarebore adaptor on that then witha bit of machining lathe out a groove for the "bell" addaptor to sit in, then drill & tap a couple of small bolt holes to hold it together.... then finnally bolt the mixer on as normal !........... maybe next w/end
Kingy
[color=blue][size=150][b]And your cry-baby, whinyassed opinion would be.....? [/b][/size][/color]
