I just ordered a set of stage 1 heads and i bought Brads's EVT muffler.

I cant swing the intake and carb now so im going to use my stock intake and carb.

I have seen pictures of the work that some of yall have done to your stock intakes and carbs so lets see what you have done.

Also, any tips on tuning the stock carb???

Are you putting both on at the same time? I am curious what the gains would be from just the heads with the stock muffler...and then what are the gains after adding the muffler. At least that way you know where the gains came from, to a certain degree. I'm not sure how much of a pain in the ass it would be. I've never installed a muffler on my PD, so I don't know what's involved.

Everyone seems to disagree about the improvements from each individual mod, especially heads. I have heard the gains from headwork are different for every motor, depending on how well your stock heads were made. It seems as though a lot of people do multiple mods at the same time, which makes it difficult to evaluate them individually. I know they all work in together but like I said, I am just curious.

I know Deadbird8 has done a lot of work on stock intakes and carbs. The pictures of his work look impressive, but for all I know I could be looking at a Peterbuilt intake.

try it! ain't no one but you spendin u'r money but u
let me know how it works!

with my old motor that is the setup i ran. I tried all the aftermarket carb and intake 3 differant setups to be exact and went back with the stock. I gained almost 2 mph with aftermarket carb and intake and lost alot of bottom end. i'll trade bottom end for 1-2 mph any day of the week!!!

I did the heads first and they produced a slight gain with everthing else being stock, then I put on an aftermarket muffler and once again a slight gain there also. In went a BPS cam which seemed to help somewhat with a load by installing it, so one week later on went the EVT intake and the S&S which = 27% gain on speed and a major reduction in MPG when compared to having the stock carb and intake on it.
Still running stock rods, pistons, pushrods and rockers with no problem to date.


The rework Deadbird8 did may be an ideal setup, if one doesn't want to spend a lot of funds overall.

I did headwork after exhaust and ran the stock carb with good results for about 80 hours. My motor responded well to the exhaust, K&N, and headwork (0.060) in top end as well as load carrying capability.

I've done a bunch of these stock intakes for the horizontals- sorry don't have a vertical intake pipe to exchange for you. Used a carb spacer to combine the carb chambers. The intake port is beveled to a knife edge and opened up to match the gasket size. The head ports are bored out to match the gasket/intake ports on the heads and all the bends are softened to increase flow. I modified some 80 grit flexhones and run them through the whole pipe with a flex shaft on the drill to smooth them out, the rest is done with a dremel over a cup of coffee. I bored out the 90 degree piece that goes from carb to intake on the horizontal (I don't think you have that piece) and put a mirror finish on the 90 piece that goes to the air filter plate (not sure if you have that either). There is a plate on the horizontal's air filter that I opened up as well to get rid of that 90 in the air flow. I used a K&N E4665 filter to increase flow. If you think about it, the difference between the 35 and 36 Briggs is the intake air flow.

On the carb, removed about 1/2 the bulk on the shafts between the plate screws on the throttle and choke shafts and made them aerodynamic (like a plane wing). Removed the big screws/lockwashers on the plates and replaced with low profile buttonhead screws locktited in. Cutting down the shafts/screws was dynoed at a 0.5HP gain and someone also calculated the airflow area increase of 14% in the carb chamber. Cut the tabs off the black caps on the idle adjust screws on top of the carb to richen up the idle due to the carb spacer (start about ~2 1/2 turns out vs. 1 1/2). I also removed the fuel shutoff solenoid and just plugged the hole with a bolt like MB does on their 45s.


You can run the stock main jets in the carb. If you need more fuel, you can match the #1 jets in both sides because the carb spacer mixes the fuel. I think Hoyt at GT does some other tweeks to the stock carb but I'm not sure of the details.

Alot of tinkering but it worked well for me, especially throttle response (got rid of the big bog down when you mash the throttle). While the heads were off for work I had some time on my hands. I picked up most of these tips on this forum from the folks that did alot with the stock carbs before going to the Mikunis. (especially Rail and rg567). My original intake was done by Silk at EVT. When I put a BPS Mikuni kit on mine, I bolted a reworked stock intake and my old setup on a buddy's 45HP and he gained over 200RPM with "night and day" throttle response. I just sent another setup to Bill down near Houston (can't remember his name on this forum)- he is installing now but converting to a tall transom outdrive with a new boat. I haven't got any feedback yet. Intake work is probably only worth the trouble if you are installing heads (taking it off anyway) as the gains aren't quantified on a dyno but I'm sure they don't hurt.

Hope this helps.



You can see the gasket line on the original intake.

dat looks real good db8!
great reply!

Thinking of going this route as well.

Still looking for the old threads here, and on the old forum. It seems I remember some of the origginal machinists that did Head work and kept the carb stock were either zip tying about 3-4 coils on the stock governor spring together which increased their RPMS in the water. Some of them were turning the prop up to 4500 rpms. Another thread which I can't find, some with stage one headwork were using a different color governor spring they got from Mudbuddy and gave some of the same results of about 4400-4500 rpms in the water.

DDM, do you recall what Rpms you were turning with the stock carb and the Headwork? I think you had modified your stock ebaust as well, or was that EVT exhaust?

Soemthing to be said about this set-up if DDM tried them all and went back to it, especially if you are looking for bottom end with a little top end. If the head work is done as well, if think the overall component reliability should be pretty high considering that you won't be revving up as high without the Mikuni. Something to think about as well.

BTW...maybe because I am in the middle of thinking of all this myself, but this has been a meaningful and civil discussion.

I'm running the same setup that DDM used to run. I am running the stock carb and intake also. The aftermarket carb & intake will give you about 1-1.5 mph extra on the top end but you will lose a good bit on the bottom end. Thats why I stayed with the stock carb & intake. I am turning 4200-4300 rpms with this setup.

This is some good stuff! This really helps alot.

As far jets, is everyone doing the same??? Running the same jet in each hole? Terry, what were you doing as far as jets?

And what about those little screws on the top of the carb with the plastic deals? how would i benefit in adjusting those?

Those are the idle enrichment screws to adjust the fuel at idle. You set your idle, and adjust them where your idle begins to really smooth out.

The tabs on the black caps keep you in the range of around 1.5 turns out. If you add a carb spacer or need more fuel at idle, then just cut off the tabs that restrict the movement and you have full range to adjust. Some people take the whole cap off and notch the brass knob that is left so you can adjust with a screwdriver. I have done both and cutting off the tab is easier.

The tabs restricting adjustment outside of a certain range may be an emission control thing or something. Not really sure on that its only a guess.

I'm running stock jets.

stock jets!!

heads, cam, modded stock intake, exhaust, K N filter, advanced timing with stock jets. motor runs great.

Bump from way back

Very good an reliable setup ALOT of guys fail to consider. Heads, cam, and exhaust is a GREAT combination.

Does anyone know of any machine shops in or around Baton Rouge who could deck the heads and do the three angle valve job?