360 question?

-
I don't think you could go wrong with vac secondary Quick Fuel carb. They are top notch parts.
 
Street driving your not gonna see much of a difference between a 650 or 750...
 
isn't the quick fuel a race type carb?

Not their street slayer series vacuum secondary carbs. Quick Fuel, just like Holley, have different versions of carbs from mild street to wild race carbs.

You'll have to use an adapter to bolt the Thermoquad up to your intake because the TQ is a spreadbore carb and your intake is made for square bore carbs only. If you don't mind doing that and you have a Thermoquad that your sure is rebuildable and your capable or know someone capable of rebuilding it might be a good choice. In the end you can do as you please but for a 385 horse engine I wouldn't use anything less than a 700 cfm carb. Your just giving up horsepower you paid for if you do. Why did you use 5200 rpm as the rpm limit in the calculator? I'd be really surprised if your 360 made it's peak of 384 hp at that low rpm.

One thing to keep in mind about most carb calculators is they don't take into account for the space fuel takes up in the airstream so they generally predict the size quite low. Wish I could remember the formula for the space the fuel takes up at a WOT ratio of 12.8~13 to 1 where you generally make the best power it but at the moment it escapes me but I remember using Holley's calculator and it said my 450 hp 408 only needed a 697 cfm. I know for a fact by testing that it runs much better with a 850 vs. a 750. That proves the calculators aren't always accurate due to the restriction fuel presents in the venturi's.

One last thing, why are you second guessing the professionals that built the engine? Seems to me they'd know what worked on it the best. As for their recommendation of a 780 being too much for a daily driver. Too much in what way? I've seen guys run dual 1050 dominators on a tunnel ram on the street and they performed fine. You have to remember that a carb doesn't magically force it's max cfm down the engines throat, the engine draws what it needs in conjunction with how far you press your right foot down. Can you over carb your engine, sure! Is a 780 too big, no way!
 
Not their street slayer series vacuum secondary carbs. Quick Fuel, just like Holley, have different versions of carbs from mild street to wild race carbs.

You'll have to use an adapter to bolt the Thermoquad up to your intake because the TQ is a spreadbore carb and your intake is made for square bore carbs only. If you don't mind doing that and you have a Thermoquad that your sure is rebuildable and your capable or know someone capable of rebuilding it might be a good choice. In the end you can do as you please but for a 385 horse engine I wouldn't use anything less than a 700 cfm carb. Your just giving up horsepower you paid for if you do. Why did you use 5200 rpm as the rpm limit in the calculator? I'd be really surprised if your 360 made it's peak of 384 hp at that low rpm.

One thing to keep in mind about most carb calculators is they don't take into account for the space fuel takes up in the airstream so they generally predict the size quite low. Wish I could remember the formula for the space the fuel takes up at a WOT ratio of 12.8~13 to 1 where you generally make the best power it but at the moment it escapes me but I remember using Holley's calculator and it said my 450 hp 408 only needed a 697 cfm. I know for a fact by testing that it runs much better with a 850 vs. a 750. That proves the calculators aren't always accurate due to the restriction fuel presents in the venturi's.

One last thing, why are you second guessing the professionals that built the engine? Seems to me they'd know what worked on it the best. As for their recommendation of a 780 being too much for a daily driver. Too much in what way? I've seen guys run dual 1050 dominators on a tunnel ram on the street and they performed fine. You have to remember that a carb doesn't magically force it's max cfm down the engines throat, the engine draws what it needs in conjunction with how far you press your right foot down. Can you over carb your engine, sure! Is a 780 too big, no way!


thanks...that info was super helpful. the dyno sheet said the engine was run from 3300 to 5600 rpm....the peak horse was at 5300 rpm
 
thanks...that info was super helpful. the dyno sheet said the engine was run from 3300 to 5600 rpm....the peak horse was at 5300 rpm

Your welcome. Sounds like it's pretty efficient to make 384 hp that low in the rpm range

Do you have a way to post the dyno sheet. Just curious.
 
not at the moment...what do you wanna know? i can tomorrow after work when I go back home to work on my car
 
650 work fine but your just gonna want a 750 in a week so save 250.00 and get it now

letter BREATHE

True that....... I would skip out on the Eddy. Just took off a 600/1406 with Vac Secondary's off the car I bought that has a Stockish 340 in it with a purple cam. I rebuilt a 700DP Holley for it with all the good stuff. Crisp clean throttle response and no waiting for the Vac Can to open the secondary's!!
 
I run a Holley 770 Street avenger onmy 360 street car love it, easy to tune, affordable also.
 
ijust purchased a quick fuel 780 cfm...figured I'd giver a go

I think you'll like it. Generally right out of the box their tuned pretty good but depending on how big your cam is you may have to put a lower rated power valve in it (you'd have to do that with most any carb you got, not just the quick fuel). You could probably call the place you got the engine from and ask them how much idle vacuum it pulled (your dyno sheet may say, but most don't). You want the power valve to be rated at approx. 60% of the idle vacuum. In other words if the engine pulls 11" of vacuum at idle you'd want a 6.5 power valve which I believe is the size they come with.
 
I think you'll like it. Generally right out of the box their tuned pretty good but depending on how big your cam is you may have to put a lower rated power valve in it (you'd have to do that with most any carb you got, not just the quick fuel). You could probably call the place you got the engine from and ask them how much idle vacuum it pulled (your dyno sheet may say, but most don't). You want the power valve to be rated at approx. 60% of the idle vacuum. In other words if the engine pulls 11" of vacuum at idle you'd want a 6.5 power valve which I believe is the size they come with.

vacuum is 13.5 at 900 rpm
 
That's a good carb, and defintely not too big. I'd start with an 8.5 power valve and go UP from there, with 10.5 being the max. Driving the car around will tell you which one, but I bet the 8.5 will be fine.
 
vacuum is 13.5 at 900 rpm

Is that the idle speed, or just where they logged it? 900 rpm idle is pretty high unless it has a pretty big cam. I'd leave the carb as is until you get it in the car and see what the idle vacuum is sitting still in drive.

Do you know what cam they put in it?
 
here got some better pics of the engine
 

Attachments

  • 0420131136.jpg
    105.4 KB · Views: 171
  • 0420131136a.jpg
    104.4 KB · Views: 176
I am going down the same path. Looking at a 360 crate (408 stroker) for my 70 swinger. What headers are you using? Hoping for a good fit My car has power steering. The car had a 318 originally with auto trans.
 
I am going down the same path. Looking at a 360 crate (408 stroker) for my 70 swinger. What headers are you using? Hoping for a good fit My car has power steering. The car had a 318 originally with auto trans.

right now i have hedmans on my 318 I have in there....ttight fit thats for sure had to lift the motor out to get them on...I wanted to get hooker headers cuz my dad has them on his 70 swinger and he said they fit really well...but I might get doug's or tti's go big or go home deal. I have power steering too but I'm going to manual steering for more room and my power steering leaks haha.
 
right now i have hedmans on my 318 I have in there....ttight fit thats for sure had to lift the motor out to get them on...I wanted to get hooker headers cuz my dad has them on his 70 swinger and he said they fit really well...but I might get doug's or tti's go big or go home deal. I have power steering too but I'm going to manual steering for more room and my power steering leaks haha.


Hookers may fit well (as in clearing all items) but they are the same design as your Hedmann's so installation is exactly the same. In fact all cheaper headers are modeled after the Hooker/Hedmann style header. Doug's or TTI are the only that are different and easier to work around.
 
they recommend a 780. i would run at least a 750 but would go with their recommendation on a 780. hell they built the motor and know what needs to be on it.. a 625-650 will be too small for it.. as long as the rest of your combo is matched to the motor and the 780 tuned properly the car will be fine on the street.

that intake looks like a performer rpm to me.
 
-
Back
Top