So anybody try a wideband O2 on a crossrammed Hemi yet?

[Fran Blacker]

That fuel pump is interesting, what brand? Wonder if it holds the heat causing fuel to boil in low demand times?

 

[2blader]

That fuel pump is interesting, what brand? Wonder if it holds the heat causing fuel to boil in low demand times?

Not sure. It is a pump used by Barton years ago. He told me they suck. Just haven’t gotten around to swapping it out but it is time now. Also thinking I may go electric as the manual pump gets heat soaked from the block? I have a brand new Carter here in the box. Just trying to figure how far I wanna go with re plumbing. I may move the regulator and replace all the hard line too. Have had a ton of issues with the car so I may just do that. The hard lines are too close to the exhaust in a few spots and if you change the bends then it is too short.

 

[stage3]

Mine is a stick car so I wanna get the idle down from 1500. I can get it around 1100 but like I said above when everything got warm it stumbled. I am asking is 150 degrees is too hot for a a fuel line to get at the carb inlet? Cannot even touch it for long. That means the fuel is extremely warm/hot too which causes idle issue from vapor lock. It also surges a little here and there. Coming from BBC Chevelles with a single carb this is well new to say the least.

thats really close to the exhaust, can u wrap it with some type of shielding, like header wrap material. if it was mine i would sleep better knowing it had a heat barrier.

 

[2blader]

thats really close to the exhaust, can u wrap it with some type of shielding, like header wrap material. if it was mine i would sleep better knowing it had a heat barrier.

I may even redo the entire setup and move them at this point. They are THAT close.

 

[Fran Blacker]

my secondary idle screws with custom wrench.
with the QFT metering blocks and secondary jet plates with smaller idle bleeds its real close.
squared the primarys to transition slots and only adj idle with the secondarys, idle is at 1500 and drops to 1000-1100 in gear. does not load up. all 4 mixture screws r responsive with these qft blocks.
holley 770 cfm 4235-36.still playing with diaphram springs. purples r now in and going to long yellow springs. i think it needs more secondary jet plate. lean pop under hard acceleration.

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Is it a 8-32 x 3/8" bolt with a 1/4" head? Isn't a wrench ignition wrench set. I have a 1/4"that's 3/64 th thick wrench from a Cox GT 40 slot car kit for adjusting mine.

 

[stage3]

5/16 bolt head 10/32 thread. the custom wrench shown is a craftsman 9/32 opened up to 5/16. works great with the jaw straight up turning the screw.

 

[Fran Blacker]

They must've changed the thread, assuming you have 4235/6 carbs? Mine are 3116's forget exact month but think Nov. 64 8/32. Thanks

 

[2blader]

Whelp, a small update. Found the hard fuel line touching the exhaust. (NOT MY WORK). The fuel filter is just too close to the muffler. Knew it was like that. I also had a fuel pump by on the Racepumps.com on the engine. Barton told me to remove them as they suck. So putting on a new Carter and replumbing the the system. While doing this I removed the fuel pump shaft and noticed it looked like a shaft for a regular solid camshaft instead of a roller cam. I for some reason thought my engine had a roller cam. Looked in my folder I got with the car and came across the bullet cam card. Looked it up and it seems to be a regular flat tappet. Will call Monday to confirm but if true now I know why this thing is such a nasty bastard. I maybe changing cams in the off season as my belief is a roller is more streetable with the same specs…correct? Pic of cam card also and my Hemi is a 472 not big CID Hemis like many of you run. Thanks for any insight….Scott

 

[stage3]

thats alot of duration @.050 for a street motor solid flat tappet, my roller comes in at 272-276 @.050, .675 lift and is borderline too much for street use but my springs r spec'ed at 290 lbs closed and 550 open so with my isky redzone lifters its a matched set...But i know i would be better off with CC .650 roller, 260-268 @.050 which i had in my last motor. good street manners, adequate vacuum, and made good power. but its so close now unlike yours it would be a big PITA to change it for so little gain/loss.....my 2 cents.

 

[2blader]

thats alot of duration @.050 for a street motor solid flat tappet, my roller comes in at 272-276 @.050, .675 lift and is borderline too much for street use but my springs r spec'ed at 290 lbs closed and 550 open so with my isky redzone lifters its a matched set...But i know i would be better off with CC .650 roller, 260-268 @.050 which i had in my last motor. good street manners, adequate vacuum, and made good power. but its so close now unlike yours it would be a big PITA to change it for so little gain/loss.....my 2 cents.

Yea, thinking I will pull mine and also change head gaskets too as they seem to be seeping oil a bit. Drive me nuts. This engine is around 16 years old and doubt it has 1000 miles on it.

 

[68 HEMI GTS]

Whelp, a small update. Found the hard fuel line touching the exhaust. (NOT MY WORK). The fuel filter is just too close to the muffler. Knew it was like that. I also had a fuel pump by on the Racepumps.com on the engine. Barton told me to remove them as they suck. So putting on a new Carter and replumbing the the system. While doing this I removed the fuel pump shaft and noticed it looked like a shaft for a regular solid camshaft instead of a roller cam. I for some reason thought my engine had a roller cam. Looked in my folder I got with the car and came across the bullet cam card. Looked it up and it seems to be a regular flat tappet. Will call Monday to confirm but if true now I know why this thing is such a nasty bastard. I maybe changing cams in the off season as my belief is a roller is more streetable with the same specs…correct? Pic of cam card also and my Hemi is a 472 not big CID Hemis like many of you run. Thanks for any insight….Scott

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That’s a solid flat tappet. My buddy ran the same cam in his 472 (Barton built). His was around 12.1, ran super strong. Ran 10.40’s through tail pipes in a full weight 68 B body. He drove the piss out of that engine on the street for years.

 

[2blader]

That’s a solid flat tappet. My buddy ran the same cam in his 472 (Barton built). His was around 12.1, ran super strong. Ran 10.40’s through tail pipes in a full weight 68 B body. He drove the piss out of that engine on the street for years.

Yea, it is a stout cam but a tad much for me. Just deciding what to do at this time. I want less duration than 283 at .050. and something that will idle closer to 1000 rpm instead of 1200-1400 rpm. This will give me an excuse to take care of other things all at once. The head gaskets seep oil so it will all get done at once...along with anything else I can think of. Not sure if I want to go roller or just go with another flat tappet.

 

[68 HEMI GTS]

Got my Hemi going. I have a pair of L88 vacuum 850’s on it. List 3418. It was stupid fat with the factory calibration. Right around 12’0-11.9 at idle. Idle screws were un-responsive. Went into the 10’s with some throttle and was just loading up. Made my first whack at it, dropped the IFR from .038 to .032 on the primary. Added a transfer slot restriction of .059. Drilled the primary plates to get back on the idle circuit. Instantly better. Idles in the 14’s and starts with just a bump of the key. Goes into the 12’s when I rev it up. I’ll lean it a bit more once I can drive it. I have a few other issues to straighten out but it’s running good enough to move it around without killing the plugs. Gave it a half throttle hit in front of the house and it has stupid power..

 

[Fran Blacker]

Finally put 8/32 X 3/8" BOLT to adjust the secondaries. Thanks Stage3 . Have a restricter with a .030 hole in metering block IFR, completely closed primary throttle plates. Set the adjusting to just touching but not opening primary plates. Adjusted secondary throttle plates open a crack.Started the Hemi up it sounded really different. After running only a minute or less the thing would idle. After it warmed up I closed the secondaries to lower the idle some. Throttle response was crisp. Picture 1 (CROPPED OUT ARROW ON LOWER HOLE) is where I tap for a brass set screw with a .030 hole on both sides on both carbs. 2nd picture of bolt for secondary adjustments. Had to grind hex thinner so secondaries could be closed Note 2 bolts on right one is cut. 3rd is bolt installed red arrow. My carbs are 3116 Oct 64 so the 8/32 bolt maybe different on later carbs.

 

[stage3]

completely closed primary throttle plates.

u dont want them completely closed,,,u want them so as looking from under neath the transition slot is squared by adjusting the primary throttle plates accordingly...That way u can tune the idle air screws more accurately. doing it like that mine idles great and have Instance throttle response..

 

[Fran Blacker]

Even with the plates closed the trans slot is rectangular. This was a starting point, it was a tremendous change from before. I was really surprised and hadn't planned for doing anything but getting it to idle which it did. Just closed the secondary some with an 8th turn on that bolt. Thanks for the advice.

 

[stage3]

Even with the plates closed the trans slot is rectangular.

that is what u want

 

[2blader]

Yup this change helps alot and made a few of these for a few friends with non Hemi engines. I will be back to the O2 stuff after I replace the cam shaft in my Hemi. I ordered a new cam from Bullet that is NOT so aggressive. Mine should have never been in a street engine with so few cubes. Just waiting on the cam and getting that done, new head gaskets as one is seeping a bit and new freeze out plugs as one is also seeping. I think I am also going to add a hydraulic T/O bearing too since the engine and trans is out. Gonna have the trans gone through too.

 

[68 HEMI GTS]

So I’ve been tuning on mine. The Barton intake distribution seems kind of funky. I have a dual band innovative. I was working on some 1.610 Venturi double pumpers but thought the 770 cross ram carbs may carry more velocity and help the distribution. Doesn’t really seam to be the case. Anyway, I used a BLP primary metering block instead of messing with the origional 770 blocks. Currently running a .031 IFR which has me 1.25 turns out on the idle adjustments. Runs around 14.5 at idle. I ended up adding a transfer slot restriction to the main body’s. .078 driver carb, went to a .076 passenger carb. That put the low speed cruise in the 15’s, which it seems happy with. Currently 76 primary jetting with a .070 pvcr. Actually went WOT today on it, it’s fat. Going to go from a 81 secondary jet to 78’s and see if it cleans up from the 11.0 it was at. Probably do some more fine tuning and even stagger jetting if I need to but it’s coming around.

Where I started

Getting better

#5 and #8 fighting me before the TSR was added.

#8 coming around. I haven’t checked #5 since my last TSR adjustment.

 

[68 HEMI GTS]

I may have 5 fixed too, gonna need some more drive time. Good reminder and A/F gauge is a tool and not an absolute. Gotta read those plugs!