I just rebuilt my 300 inline 6. New pistons, rings, main bearings, cam, cam bearings, water pump, oil pump, lifters, springs, gaskets, resurfaced the valves, ground the valve seats, etc... I am just not getting the performance I expected. The only thing I didn't touch was the Carb. Should I rebuild it or look for a new one? It is a 1 bbl Carter. If I should look for a replacement, what would be the best? Thanks.

 

I'm curious. If you wanted better performance, why did you rebuild it all the same parts? HP with the 300 is about helping it to breathe. A one barrel carb is sad. It just doesn't breathe.

You could remove the int/exh and install a 4v intake, clifford or Offenhauser, with a nice little 4v carb. The Holley 390, Autolite 4100, and the Edelbrock 500 are common choices. Those parts insure more air mix in. To equal hp improvement, you need to insure a better than oem exhaust system. A good improvement would be a set of efi manifolds from the j/y for about $40, along with a good muffler/pipe.

Better yet would have been to port and polish the head. That opens up the bottleneck of these heads, and allows the engine to breathe. Another step would have been to install an aftermarket cam.

But if you do the carb and exhaust, along with a good ignition system, msd, mallory, or Summit racing, with a hot coil, you'll see quite a bit of improvement.

 

Pretty much everything F-250 said.

You're not getting a lot of performance out of your rebuild because you rebuilt it to stock. The stock 300 just isn't a performance engine.

That said, it doesn't take much to wake them up.
I noticed huge gains over stock just by putting on EFI exhaust manifolds and a 2.5" exhaust. Even more when I added a 4bbl carburetor.
Just those two things alone were enough to make me plenty happy.

 

these guys are right rooster if your looking for performance then that restrictive one barrel has to go, listen to f250, AB, and many others on this forum! I'm in the process of doing a little build of my own once i park my truck for the winter (offy dp, eddy 500 carb, and hedman headers, oh yeah porting my head ) i think what f250 has always told me to research, read, and save in a folder!

good luck on your choices

 

Thanks guys. I did rebuild it to stock. I am not looking for "performance" I guess. It is my daily driver. I should have explained myself better. The 1 bbl just isn't performing. I am going to look into some of the options you gave me.

 

I believe most individuals have an inaccurate expectation, not that the 300/4.9 has a lack of performance. I believe the 300/4.9 has met and or exceeded the manufacturers expectations of performance. I know it has mine.

Definition of EXPECTATION

<!--INFOLINKS_ON-->1
: the act or state of expecting : anticipation <IN <i>expectation</I> of what would happen>

2
a : something expected <NOT expectations> <expectations for an economic recovery> b : basis for expecting : assurance <THEY expectation of success> c : prospects of inheritance —usually used in plural

3
: the state of being expected

4
a : expectancy 2b b : expected value

— ex·pec·ta·tion·al<INPUT class=au title="Listen to the pronunciation of expectational" type=button itxtBad="1" itxtNodeId="97"> \-ˈtā-shə-n<SUP itxtNodeId="99" itxtHarvested="0">ə</SUP>l, -shnəl\ adjective

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Definition of PERFORMANCE

<!--INFOLINKS_ON-->1
a : the execution of an action b : something accomplished : deed, feat

2
: the fulfillment of a claim, promise, or request : implementation

3
a : the action of representing a character in a play b : a public presentation or exhibition <A performance>

4
a : the ability to perform : efficiency b : the manner in which a mechanism performs <ENGINE performance>

5
: the manner of reacting to stimuli : behavior

6
: the linguistic behavior of an individual : parole; also : the ability to speak a certain language — compare competence 3


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The reason I posted this is as I have owned and driven a few different BB six Ford trucks and am in the process of dropping one in a Roadster I see many times people's misguided expectations are the issue not the 300/4.9's lack of performance. Do not expect a less than 200 hp inline six engine to perform like a 400 hp v8. Ain'tgonadoit

BTW TheRooster12 my 309 is a stock rebuild less the 60 overbore. When it was in the truck it performed as expected with the stock points/1barrel carb and stock intake/exhaust. My plan is to inhance the ignition/induction/exhaust. If at that point my expectations are not met, which I believe they will be, it will be time for a cam/valve train upgrade. Well, I may just do that cam/valve train for fun.

Think with your dip stick!
Jim

 

For a few hundred dollars you could feel quite a difference in performance, just by installing an Offenhauser intake, 4v carb, and the efi exhaust manifolds. The Efi's you could pick up at the j/y for about $40. The intake could be purchased used on ebay or Craig'slist for about $150-$200, and the carb can also be bought either rebuilt or just used, and rebuilt by you. Just those changes, as AbandonedBronco said, will give you a noticeable difference.

 

***** Five Stars to jem44537! Disappointment of the expectation is a result of inordinate expectation running head-on with actuality.