'66 C10 250 4.1L: 4097cc or 4098cc?

[thelawdoc]

My truck is a stock '66 C10 250 2spd PowerGlide with Rochester B carb, Dizzy-P&C. When ordering a carburetor from O'Reilly's, I have to choose between two 250cid 4.1L engines:

Select Model and Engine
Base -- L6 - 3.8L 230ci 3769cc - 1BBL GAS OHV
Base -- L6 - 4.1L 250ci 4097cc - 1BBL GAS OHV
Base -- L6 - 4.1L 250ci 4098cc - 1BBL GAS OHV
Base -- L6 - 4.8L 292ci 4801cc - 1BBL GAS OHV
Base -- V8 - 4.6L 283ci 4638cc - 2BBL GAS OHV
Base -- V8 - 5.3L 327ci 5358cc - 2BBL GAS OHV
Base -- V8 - 5.3L 327ci 5358cc - 4BBL GAS OHV

How can one tell which one they have?

[padresag]

perhaps you have the bigger of the 2. they are both the same and some one just rounded the nbr up. a cubic centimeter would not be that big spread over 6 cyls. the original measure may have been 4097.5 cc. anyway they are both 250 cu. inches.
actually 250 cu in. = 4096.766 cc
ron

[thelawdoc]

Padresag, that is what I thought, I was just put off by O'Reilly's showing like two different engines.

[TJ's Chevy]

Lets face it...the early 250's had no more then 130 hp...and the later 250's had less because of emissions...so...carb really doesn't matter...a 1 barrel is a 1 barrel. lol I'd go to Autozone if ya have one...usually they just need a year and off you go.

[thelawdoc]

TJ, I have an AutoZone near me. Today I will dismantle the carb and do a deep cleaning/examination. If this does solve the issue (see my thread re Bogging/Stalling When Braking), I will just have to buy a new carb. I would have to decide between sending mine out, buying a reman, or buying a new one off the shelf. I would not mind buying a new one off the shelf, but I hesitate because of the throttle and choke linkages. I really need to plug and play a carb here. What do you mean by 'just need a year and off you go'?

[TJ's Chevy]

Originally Posted by thelawdoc

TJ, I have an AutoZone near me. Today I will dismantle the carb and do a deep cleaning/examination. If this does solve the issue (see my thread re Bogging/Stalling When Braking), I will just have to buy a new carb. I would have to decide between sending mine out, buying a reman, or buying a new one off the shelf. I would not mind buying a new one off the shelf, but I hesitate because of the throttle and choke linkages. I really need to plug and play a carb here. What do you mean by 'just need a year and off you go'?

In all my experiences a Napa/ Autozone, All I had to do was tell them the year, make, and model of my truck, and what engine and they would give me the needed part without issue....Unlike other places which seem to need more info and Still can't figure it out. A brand new carb might be better over a reman, but if you wanted to never have issues again I'd convert to a 4 barrel. lol

[thelawdoc]

TJ, Thank you. I will check AutoZone/NAPA online. As for a 4 barrel, I am still a novice mechanic and therefore I do not see why a 4 bbl should be better than my 1 bbl as far as wear and tear. My truck is stock, a daily driver.

I found this place, Mountain Man Fuel Systems, that rebuilds carbs. He says I can send him my carb and for $125 he will make it good.

[TopFuel1966]

Assuming that your motor is unmodified and peak RPM is somewhere around 4500, the figures dictate a carb size of around 250 CFM, making even a small 500 CFM 4 BBL 100% overkill.

[thelawdoc]

Topfuel, I am going to dismantle the carb today, deep clean and triple check the float levels, and if still not good, I am leaning toward the Autozone reman Roch B. (Autoline C935) A little pricey, but it seems to be my exact carb. My truck is stock, a street daily driver. The symptom I am trying to be rid of is described in my thread Bogging/Stalling. Thanks.

[TJ's Chevy]

Originally Posted by TopFuel1966

Assuming that your motor is unmodified and peak RPM is somewhere around 4500, the figures dictate a carb size of around 250 CFM, making even a small 500 CFM 4 BBL 100% overkill.

A 500 cfm edelbrock would do that 250 alot of good...add hei and headers and it makes things better. But he's keepin her stock so no need to worry.

[thelawdoc]

This is a photo of the Autoline c935 carb that I would replace mine with. It appears to be my same Rochester B, except that, if you look at the top left in the photo, within the throat, it seems to have like some kind of stubby air inlet or airhose nipple. My Roch B does not have this and I am wondering what it is for and whether I need to attach something to it. Autozone did not know what to tell me.
http://contentinfo.autozone.com/znet...935/2/image/3/

[TopFuel1966]

Your symptoms might indicate that possibly your upper float setting is too low. Verify that your float settings are correct allowing enough fuel into the bowl before the needle valve closes.

[thelawdoc]

TopFuel, I will certainly check that float. You understand, that the stall only happens when I brake, and that idling, running, power, etc. is all nice? (Idle set at 900. Lower rpms does not give me smoother idle.)

[TopFuel1966]

If there is insufficient fuel in the bowl when you brake or accelerate it may be causing the main jet in the bowl to be momentarily uncovered and starved for fuel. Kinda like if you allowed the gas level in your tank to get so low that the gas would run away from the fuel line connection momentarily when you went around a corner.

[thelawdoc]

TopFuel, understood. Thank you.

[thelawdoc]

TJ, well, if it turns out that I do, in fact, replace my carb, exactly what 'good' might I expect from that 500 cfm edelbrock with my otherwise stock engine? I was thinking of swapping in an Autoline c935 from AutoZone, cost $200, which appears to me to be a rebranded Rochester B.

[TJ's Chevy]

Originally Posted by thelawdoc

TJ, well, if it turns out that I do, in fact, replace my carb, exactly what 'good' might I expect from that 500 cfm edelbrock with my otherwise stock engine? I was thinking of swapping in an Autoline c935 from AutoZone, cost $200, which appears to me to be a rebranded Rochester B.

You will have to change to a different intake and swapping to headers would be a good idea....Anyhow...with a 500 cfm edelbrock, headers, and hei you get little better mileage and power...When I switch to a 4 barrel and headers on my 292 I could almost do a burnout without dumping the clutch..and that's with an old wornout 48 year old engine...so..but if yer wanting to stick to stock manifolds then a 2 barrel will be easiest...and will make a little difference as well. With a 4 barrel, headers, and hei you probably see maybe 30 hp over stock...and that's where head work make the huge difference.

[thelawdoc]

TJ, yeah, I know from reading these forums of all these mods. Me, I am but a grasshopper when it comes to these trucks. I can wrench my simple, stock 250 by using the manuals and you guys here. If I start souping things up, I am going to bury myself. Remember, up until a year ago, I did not know a truck from a canoe. I am 58 years old. I think it will take me another 10 years until I know what I have now under the hood. I don't think there are enough years left for me to gain proper knowledge of headers, etc. such that I start modifying my truck. You need to understand: just this week I became comfortable doing timing! Remember how you felt when you were 13 years old and did timing? That is how I felt this week. Like a man. Look at the title of this thread- until today I did not know that there is no difference between 4097 cc and 4098 cc. And I am going to start messing with headers? God help me, lol. You guys will go crazy trying to save my ass.

[TJ's Chevy]

Originally Posted by thelawdoc

TJ, yeah, I know from reading these forums of all these mods. Me, I am but a grasshopper when it comes to these trucks. I can wrench my simple, stock 250 by using the manuals and you guys here. If I start souping things up, I am going to bury myself. Remember, up until a year ago, I did not know a truck from a canoe. I am 58 years old. I think it will take me another 10 years until I know what I have now under the hood. I don't think there are enough years left for me to gain proper knowledge of headers, etc. such that I start modifying my truck. You need to understand: just this week I became comfortable doing timing! Remember how you felt when you were 13 years old and did timing? That is how I felt this week. Like a man. Look at the title of this thread- until today I did not know that there is no difference between 4097 cc and 4098 cc. And I am going to start messing with headers? God help me, lol. You guys will go crazy trying to save my ass.

Well, for one thing...and you won't believe this, but I'm 15 years old going on 16...so I clearly remember setting timing when I was 13! LOL! I've been into these since I was 8 so...had a few years on them anyhow.

[thelawdoc]

TJ, Wow, I thought I was talking to someone older than myself! I did not think guys your age had much interest in cars anymore. I am impressed even more than I am usually impressed when I come to the forum. I should amend my previous post and ask: remember how you felt when you were 8 years old and set timing?....