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Topic Review (Newest First)
11-20-2005 07:42 PM
xntrik 1) over cammed for what you want
2) over carburated on the primaries
3) timing curve?

400 hp from a 305 cube..... = 131 %

That ain't no street engine Forrest.

Like they said, stall speed and gears.
11-17-2005 12:27 PM
itsnotbutter! Dont know much about the whole over carb issue but a friend of mine is running a 390 76 Ford with a a 600cfm holley and he told me that n e higher of carb would realy mess up his combo.... i can say all he has but its not like a "pro" or any thing ... he gets avg (when hes not acting an *** on the gas) 18 mpg and he'll hit 100mph VERY i mean VERY fast. Try selling you carb and just go with a smaller one... or start over ??
11-09-2005 04:40 PM
jeff bonnell for the most part i'm in agreement with most post's , a looser converter and steeper gears would do wonders , also a smaller cfm carb would probably help too (i remember as a teen , bigger has got to be better!) . while i agree a 305 isnt the prime candidate for scaring old ladys and rattling the neighbors windows , if done right , they can be just *** bad *** as a 350. my suggestion would be if you're gonna spring for a looser converter, spend a few extra bucks and put in a shift kit as well , that would up the fun factor 2 fold
11-09-2005 01:23 PM
Tech @ BG That carburetor may be too large for your application. If you have room try installing a 4-hole spacer between the carburetor and intake manifold. It will help increase the air velocity a little and make the carburetor act a little smaller.
11-07-2005 04:22 PM
steve t if everthing else fails , go to a line lock for burn outs
11-07-2005 04:12 PM
poncho62 Also, you said a"Pro" built it....Well, a real pro would have been talking you into starting with at least a 350. You would have been much further ahead. I have a feeling that your 305 isn't putting out near what you think it is.If it was, you would be more than happy with it.

I agree, that there is a bad combination of parts here....not necessarilly the carb.
11-07-2005 03:40 PM
2NDXRND I have to agree w/ the "over-carbed" crowd. I had a Carter 625/mech. choke on a mild 351W. the P.O. had done some jetting on the carb because he thought the 625 was too small. The car ran like a pig and was getting 6mpg. I pulled the 625 and went with a 600 Edelbrock............. WHAT A DIFFERENCE! Much more power, and over doubled the mpg's.
Also, not to bust on anyone, but 400 real H.P. from a 305 would be quite a feat. I think Demon makes a 500 cfm 4bbl w/ electric choke.... maybe its a 550 cfm. Those may be closer to the needed size.
11-02-2005 01:45 PM
killerformula I think we need to hear more specs about this motor to recommend what to do with it. I have a felling after we hear the specs of this build that this 400 horse 305 is going to turn into a 220 horse 305 in a hurry.

11-02-2005 09:34 AM
stepside454 drum, you said in the original post that this 305 is in the 400 HP range. If it is truely in the 400 HP range than this 305 would be a serious effort engine, with a RPM range requiring a really loose convertor, that wont have squat for low end torque...... or.... it is far from 400 HP... & you dont have the right combination of parts. a small bore engine like a 305 is very easy to over cam & over carb. 600 CFM is enough carb for even the healthiset street 305s. Give us some more info, we'll see if we can help.
11-02-2005 09:01 AM
Originally Posted by Centerline
Gears and converter are a must.
When I first got my '86 Monte Carlo SS, it had a L69 305 with a compucam 2040 cam...

I had a rebuilt 200-4R put in to replace the failing one. I also installed a 2500RPM stall. You could really feel the difference with the new stall convertor.

With my new 355, I don't feel the looseness of the convertor as much...

what are the specs on the cam are you running? and what rear gears are you currently using?

Go with 3.42s and a 2500 stall, that will wake it up!
10-31-2005 04:51 PM
Centerline I completely agree. When you had the engine gone through you changed the horsepower and torque curve and that is only PART of the equation. Now you need to modify the rest of your drive train to take advantage of your engines new peak operating range. Gears and converter are a must.
10-30-2005 09:31 PM
techinspector1 As alluded to by 67 deuce 4 me, when you changed the cam, you changed the window of operation from low r's to either mid r's or high r's, depending on the grind you put in the motor.

Any camshaft you bolt into the motor has a window of operation of approximately 3,500 rpm's. In other words, it'll be ground to operate from idle to about 4,000 r's or 1,500 to 5,000 or 2,000 to 5,500 or 2,500 to 6,000 or whatever. If you're still operating with your stock converter, it was meant to operate with a cam that is efficient at low r's, 'cause that's where the average consumer wants the power. You were able to skin the tires with the original cam, but now you are not making enough power down low to do it. You've moved the window of operation up in the rpm band. You'll have more power in a higher range, but the low end power won't be there anymore. In order to skin 'em again, you will need some gear or a looser converter or both.
10-22-2005 10:31 PM
drumharddriveanova will get more info and get back thanks
10-22-2005 10:28 PM
Originally Posted by 67 Deuce 4 Me
Sounds to me like the 4 brl may be too big. Was the whole engine rebuilt? Did you change to a larger cam? If you have one component that is too big for the set up, like heads,carb, or a huge cam on a stock converter or gears. it will be a pig. need more info.
the engine itself should be ok- it was built up by a pro that has done many engines and many race engines mines built up a lot but not for serious racing just street rod its cammed- im not quite sure how much-i dont think its too radical the engine should be ok tho and its built for the 4 brl the engine does run great and has great acceleration like i said before but i cant burn out much at all- yes the whole engine was rebuilt
10-22-2005 10:28 PM
re: carb. problem

It sounds to me like you might have the engine over carbureted. Does it "bog" off the line? Since your 4 barrel no doubt allows more air to flow through, you intake velocity will be slowed (even though your volume will be greater)...basic physics. Just like when you put your thumb over the end of a garden hose to make it spray increase the velocity. Anyway if you're sure the carb. is in good working order, maybe recalculate your carb. needs.

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