another M-1 vs Airgap question

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ColeTrickle74

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After reading every thread on the m1sp and the air gap I havent really found anything regarding nitrous use. Heres what I got so far:

360 .30 over with kb107s, stock rods and crank
eddy heads
519/524 lift 294 int./306 exh cam
3000k converter and 4.10 gears with a 727 auto
carb will be either a 750dp or a 770 street avenger
It will be a 100 or 125 shot on street driven 74 dart with trips to the track.

I have no preference between the air gap or the m-1sp, any tips would be greatly appreciated, thanks!
 
with the 3000 converter and 4.10 gears...i would use the air gap.
 
No comment on the intakes but I would use the street avenger since you are going automatic transmission.
 
Isn't the Air Gap a duel plane and the M1 a single plane? You can spray nitrous in either one. But for street use I'd go with the Air Gap.
 
oops, sorry about that, I must of forgotten to add its the single plane version of the m-1
 
Either of those carbs are more than that build can use. A 650DP would be a better choice as would the 670 Street Avenger.

A single plane would only be an advantage over the air-gap if you were turning in excess of 6000 rpm a lot. Same with the bigger carbs they may give you a poney or two in the upper reaches of the rpm range but will be a definate liability in regards to throttle reponse and driveability below 5000 rpm.
 
dgc333 said:
Either of those carbs are more than that build can use. A 650DP would be a better choice as would the 670 Street Avenger.

A single plane would only be an advantage over the air-gap if you were turning in excess of 6000 rpm a lot. Same with the bigger carbs they may give you a poney or two in the upper reaches of the rpm range but will be a definate liability in regards to throttle reponse and driveability below 5000 rpm.
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Really,well my 360 is about the same build am i'm running a 850 quick fuel,with great results at the track,street driven too!!!
 
dgc333 said:
Either of those carbs are more than that build can use. A 650DP would be a better choice as would the 670 Street Avenger.

A single plane would only be an advantage over the air-gap if you were turning in excess of 6000 rpm a lot. Same with the bigger carbs they may give you a poney or two in the upper reaches of the rpm range but will be a definate liability in regards to throttle reponse and driveability below 5000 rpm.
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I don't know about that. I have a 650 on my stock 340 with just a mild cam and the 650 I got on it is just not enough carb. It works ok but I should of got me a 750.
 
thanks for the responses, i was leaning towards the airgap. weather hit near 60 today. a little reminder i need to hurry my *** up :cheers:
 
if spraying more than 150 go with the m-1 single plane, anything less on spray the air gap will work great on the street or strip with 125 hp shot or less, i had a backfire with 150 with one a few years back, not to good:toothy10:
 
stroked 340 said:
Really,well my 360 is about the same build am i'm running a 850 quick fuel,with great results at the track,street driven too!!!
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Well if it was primarily street driven you would be happier with a smaller carb.

I have had a 600, 670, 725 and 750 on my 360. The Demon 725 was all together too much carb and was never happy below 2000 rpm. The 750 Holley was better and if I never had any other carb on it I would likely say it was good. The 750 and 725 gave about the same performance above 4500 rpm but the driveability below that was no where near as good as the 600 or 670.

The 600 was a great carb for a street driven vehicle but it did have less power above 4500 rpm compared to the 725 or 750. The 670 has as good driveability down low as the 600 and gives up nothing to the two bigger carbs up top.

My 360 is no slouch, it is making approx 370HP and has run a best of 13.7 @ 102 with the 600 cfm carb. Its not the carb that is keeping it from being faster as the miserable 2.2 second 60' time I had with the 13.7 run.

An added bonus the two smaller carbs also give my about 5 mpg more than the bigger ones.

Remember a 360 turning 6000 rpm at 100% volumetric efficiency can only move 625 cfm of air. And no engine short of a pro-stock or Sprint Cup engine is 100% efficient so the air needs are less. So going real big on the carb isn't going to by you anything and will impact the driveability at the low rpms.
 
dgc333 said:
Well if it was primarily street driven you would be happier with a smaller carb.

I have had a 600, 670, 725 and 750 on my 360. The Demon 725 was all together too much carb and was never happy below 2000 rpm. The 750 Holley was better and if I never had any other carb on it I would likely say it was good. The 750 and 725 gave about the same performance above 4500 rpm but the driveability below that was no where near as good as the 600 or 670.

The 600 was a great carb for a street driven vehicle but it did have less power above 4500 rpm compared to the 725 or 750. The 670 has as good driveability down low as the 600 and gives up nothing to the two bigger carbs up top.

My 360 is no slouch, it is making approx 370HP and has run a best of 13.7 @ 102 with the 600 cfm carb. Its not the carb that is keeping it from being faster as the miserable 2.2 second 60' time I had with the 13.7 run.

An added bonus the two smaller carbs also give my about 5 mpg more than the bigger ones.

Remember a 360 turning 6000 rpm at 100% volumetric efficiency can only move 625 cfm of air. And no engine short of a pro-stock or Sprint Cup engine is 100% efficient so the air needs are less. So going real big on the carb isn't going to by you anything and will impact the driveability at the low rpms.
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He may be happier on the street with the smaller carb,but deffinately will see much better performance at the track with a 750/850 carb.. my 360 runs 11.70's with 60's in the 1.60's..:-D
 
Thats where you need to be honest with yourself. If you go to the track once a month for a test and tune night to see how fast the car is and the rest of the time you drive on the road then a smallish carb is what you want.

A vacuum secondary carb is more tolerant of being oversize but it still better to use 80-90% of the capcity of a 650-700 cfm carb than it is to use 70-80% of the capicity of a 750+ cfm carb.
 
took your advice and made up my mind =P~

ag.jpg


as for the carb, i will definitely be at the track once or twice a month, might be doing some bracket stuff if i can get some chassis stuff done. how bad would a 770/750 be on a street? im already waiting a few minutess for it to heat up as it is, so im used to that. what other drivability issues would i run into if i over-carbed with a 750?
 
Is that an Edelbrock air gap??..it looks a little different then mine maybe they changed the script on it..as for a carb with just a trip or two to the track each month and a lot of street driving i'd go with a 750 vacuum secondary carb...
 
ColeTrickle74 said:
took your advice and made up my mind =P~

as for the carb, i will definitely be at the track once or twice a month, might be doing some bracket stuff if i can get some chassis stuff done. how bad would a 770/750 be on a street? im already waiting a few minutess for it to heat up as it is, so im used to that. what other drivability issues would i run into if i over-carbed with a 750?
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I have a 750 DP carb on my 340 in my Duster and I haven't had any drivability issues with it. I drive quite a bit in town and the throttle response and low end torque are just fine. This carb actually works better than the 670 Street Avenger I tried out.
 
With your motor and a 100 or so shot every now and then. I would run the 750DP If you don't see a lot of street time and the 770 Street Avenger if you do see a lot of street time.
 
yeah the manifold in the pic is an airgap, just a quick phone picture. looks like ill be going with a 770 street avenger, i can get one for 250-300 bucks new so its not too bad. my block was sent in to the shop this afternoon, how long does a typical place take to go 30 over and clean it up a little?
 
I'd put a 750 DP on it and toss the vacuum stuff to the curb.

My friend had a 360 built similar with a slightly smaller cam, iron heads with a 2500 convertor and 2.76 gear. It got 20 mpg on the highway and about 15 around town.

With that gear and convertor, the engine will eat up every bit of a 750DP you can give it.
 
crackedback said:
I'd put a 750 DP on it and toss the vacuum stuff to the curb.

My friend had a 360 built similar with a slightly smaller cam, iron heads with a 2500 convertor and 2.76 gear. It got 20 mpg on the highway and about 15 around town.

With that gear and convertor, the engine will eat up every bit of a 750DP you can give it.
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I agree. Put the 750 DP on mine and never looked back.
 
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