A Few 348 Questions.....help!!!!

[29Coupe348]

Ok, i have a 348, over the winter i pulled the heads off, had a set of crane #99838 springs put in, a 3 angle valve job, and a set of 1.75 roller rockers, also i changed the cam, i put in a comp 268h: .486/.486 lift, duration @ .050 219/219, 110.0 lobe seperation. with the 1.75 rockers i figure about .505/.505 lift. And a tri-power intake. The motor started life as a 250 h.p 348 single 4bbl. It has 1 3/4" headers with a 2 1/4" exhaust. Anyway here are my questions: 1. is there a secret to adjusting the rockers, i can get them to stop clanking (its not too bad, but i hear them, and its a hydrolic set-up so i figure you shouldn't hear them at all). 2. approximately how much h.p should i have? 3.i have a 3:10 posi rear in it now, and im puttin a 3:50 in it, will that help? It also have a dual point distributor with the pertronix kit in it, and the timing is set at about 15*....thanks,mike

[fatride]

First, give me the grind #s off your cam card. They will read 268- something. It's the something # I need, then I wil figure your lift. I don't think .505 is correct. The .050 duration for that cam should read 218. As for the roller rockers, They will make clatter. since they are not a one piece stamped steel rocker they have many moving parts. All moving parts have to have clearances between the moving parts, this will make some clatter. What is your compression ratio? I didn't know they made a dual point Pertronics??? Timing set at 15 dgs BTDC??? Forget the initial timing unless you had someone "professional" do your distributer. Time your engine for total mechanical advance at (depending on comp ratio for rate of advance) to 34 to 36 dgs. at 2500 to 3000 rpm and let the initial fall where it may. You should be running a vacuum advance unit hooked to manifold vacuum also, if you do not it will idle like poop unless you have the distributer recurved! I will go out on a limb here and guess your HP to be in the 300 to 335 range. Depending on the weight of your ride It's hard to judge what a gear change will do, 3.50 gears are a good compromise for cruising.:cheers

[29Coupe348]

im not at home right now, so i cant give you the grind #, but i know it did say duration @.050 is 219/219. I ment that i have the stock distributor with the pertronix kit in it, i thought it was dual point, but i maybe its single point, i dunno. Yes its 15* BTDC. Im running a vacuum advance, its hooked up to the bottom of the center carb. My car weighs between 2500-2800 pounds. I also have a B&M 2400 stall convertor in it, but it dont feel like i have a convertor at all. It feels like a dog off the line, but at about 2000 rpm it just takes off, so im hoping the gears will help that out. As soon as i get home i'll give you the grind #. Thanks for the help...mike

[dq409]

You have to know if it`s a dual point or single. Pooptronix is not the setup to use ! I Know,,,,,this is a sticky point,,,but,,,,all the problems I had with my ignition was cured by doing away with that inferior ignition setup. Yes it may work well with a low RPM stock ignition ,,,maybe,,,BUT if you want it to run hard junk it !!
You have to match your compression with your cam. sounds like you have too much cam for that engine. You have to give more info before we can help. ie: compression ,cam card .carbs,,,,dq

[29Coupe348]

The cam grind# 409 268H-5/268H-5 H11044. I beleive its a dual point, and the pertronix seems to work fine for me. The compression is whatever it was stock, well the heads were slightly milled, i guess that would bump it up a tad. And the carbs are rochester 2GC's. Last year i was on the old forum asking cam questions, and this is the cam i was told to get by numorous people, no that its in its too big?...Also, what sprak plugs should i run?

[dq409]

HUMMMMM,,,If you power brake it when does it start turning the rear tires????

[bubbletop61]

Hi guys;
For what its worth, one of the peculiarities of the 1110919 factory dual point for the 348 Hi-Horse is that it has no vacuum advance.
Gar

[tripowerguy]

Maybe I can chime in here. You have about 9 1/2 compression if you are using steel shim gaskets. I have almost the same engine in my 58. I have some head work, opened up exhaust and bowl blending. ThePertronix has no points, it is a Hall effect unit and these guys have scared me into getting a HEI. Although I have never had any trouble with my Pertronix unit. Fat is right about the timing, disconnect the vaccum and run the rpm up until the mechanical advance is all in then set the timing at 36 to 38 degrees. I have found that roller rockers are hard to adjust by sound. I used a .002 feeler gauge and ran it up till it was snug, just so you can pull the gauge through. Then take it down a half turn. That worked for me, of course I'm half deaf anyway. My engine is really pulling hard above 2500 rpm and is all done at 6200. Fatride has got the right numbers for your carbs, I jetted mine just like he said and it runs great and puts out lots of power. It does 94 to 96 mph in the 1/4 at about 14.38 depending on the track. That is with a car that weighs almost 4000 lbs. Your hotrod should be over a hundred and down in the 13.00's:cheers Roy

[tripowerguy]

Oh yeah, forgot, check your cam card it will say what your lobe lift is. Mine is .309 int. and .313 exh. take that times your 1.75 and you should have valve lift. Roy

[29Coupe348]

Roy, It comes to .500.5" of lift. I do have the steel shim head gaskets on it. Also, is there a certain sequence you used to adjust your rokcers? What are the #'s to jet my carbs? Do you feel more power with the HEI? Sorry to be such a pain, but ths is my first W-motor...thanks,mike

[fatride]

It's not the cam that's causing your problems, That cam has been run with great results in these engines, lets look elswhere. What does your timing read at idle with the vacuum can connected? Does the engine stumble out of the hole, fall on it's face? Any backfire through the carbs? Did you degree in the cam?

[29Coupe348]

It dont stumble, it just starts pulling at 2000 rpm, im thinking thats due to the 3:10 gears in it right now, im hoping the 3:50's will help that out. It dont backfire through the carbs at all. I never checked the timing with the vacuum hooked up. The motor actually runs very good, i was just mainly concerned about the rockers clattering. And also if there is anything else i can do to get more H.P. without pulling the motor apart again, i.e.: ignition, carb jetting, changing over to a dual quad set-up, etc.?...i appriciate all the help, im new to the W-motor.....thanks,mike

[tripowerguy]

I'm still running the Pertronix haven't saved up the bread to buy an HEI off ingnition man yet but will. The jets are 61's straight through and I put a modified [ weaker] spring on the power jet also drilled out the shooters on the accellerator pump. I believe that an after market 4 barrel manifold would put out more HP but then you would have just another 4 barrel engine with funny looking vavle covers. As far as setting valve lash just follow the firing order and make sure the lifter is on the heel of the cam.:) Roy

[dq409]

Getting your valves set proper will help your power come up.
Ahhhhhhh,,,,Tri-Power !! Nothing looks better,,,,Dual Quads come in second,,,,

[29Coupe348]

Where would i get the jets? Also when i do the rockers by thr firing order, some valves would be open, some would be closed, isn't there a certain sequence to go by, like at top dead center on intake stroke do certain valves, and on exhaust stroke do certain valves?...thanks,mike.

[fatride]

Here's a method that will work on any engine and assures you that you will be in the correct position to adjust the valve. Start with the engine at operating temp. Begin with the front cylinder on either bank. Bump the engine over untill the exhaust valve begins to open, set the intake vavle on the same cylinder, with the intake set, bump the engine over untill the intake valve is roughly halfway closed. Now set the exhaust valve. Work your way down each bank.

[29Coupe348]

What spark plugs do you recommend, and what gap?...thanks,mike

[fatride]

If you can find them AC R44N or the replacement plug. .035"

[29Coupe348]

great thanks.

[29Coupe348]

the guy at the auto parts store told me he didnt have r44n's, he tried to sell me r43xls, how are they?

[fatride]

A colder plug, they will work.

[SS425HP]

Just to throw in my 2 cents, I always ran 43s on the street, 42s racing. Have 43XLS in the car now. They do fine. I would think 44 would be hot??????????????

Fred

[29Coupe348]

i want to thank everyone for the help, you guys are great...thanks,mike

[fatride]

44s were the stock plug for the 348.

[29Coupe348]

is it possible for the poly-locks to go bad?...i adjust my rockers, and a few days later, they are loose again. also, does anyone make a 1.75 roller tip stamped rocker?

[fatride]

I hate to be the bearer of bad news, but, Rockers that seem to loosen after a proper adjustment may be due to a failure of the cam lobe or rocker studs pulling out of the head. Another clue would be a noisy valve train that you just can't seem to quiet down by readjustment. If the locking bolt in the poly lock is still tight when you readjust the valve I would be freaking out! :eek: :cry I know of 1.72 ratio roller tip rockers.

[29Coupe348]

well, hopefully since i just put the cam in, its not the cam, i'll have to check the studs tomorrow....who makes 1.72 roller tip rockers, and how do i get them?...thanks,mike

[fatride]

1.72 ratio roller tip rockers are made by Cometition Cams. They are Big block Chevy, stud size is 7/16ths" When you broke your cam in did you pre lube? Did you run at 1500 to 2500 rpm for at least 20 mins? Did you use GM break in lube? Did you break the cam in using only the outer spring of your 99838 set? If you said no to any of these questions you were rolling the dice when you ran the engine for the fist time. ;)

[dq409]

FAT,,,Don`t remind me !!! That was a reoccurring NIGHTMARE !!! Best to be forgotten,,,,dq

[fatride]

I have one of those too:cuss Jeeze I hate it when that happens:mad:

[SS425HP]

OUCH!!!!!!!!!!!!!!!!!!!!!! Uglier than my first wife at 6 AM.

[fatride]

Ahh yes, Only a gone gear head that would compare his first wife to a wiped out cam!:D :D :D :D :cheers ;)

[dq409]

Fred,,,You must have been married to my EX !!! LOL !!!

That bad cam and lifters only has 25 minutes of run time !!!!
OOHHHHH WEEEEE !! ,,,dq

[29Coupe348]

i brought my car to the shop...it turns out when i adjusted my valves, i didnt have a clue what i was doing, so i went a little too tight, i bent 2 pushrods. so the shop adjusted everything correctly, and my car runs great, no noise, i love it...he also put 3.70's in it, wow it moves...well anyway, thanks for all the help, mike

[Kit123]

I have a 30 Ford Coupe with a 348 (62 truck block) with Offenhauser 2X4's. I am running 3:73 gears with it. I too tried to go with a 2400 stall converter. I finally went to a 3000 B&M 10 inch converter, and took 3 tenths off in the 1/4 mile. It was the biggest single change that I made. 13.76 @ 98mph

[1958 delivery]

Where would i get the jets? Also when i do the rockers by thr firing order, some valves would be open, some would be closed, isn't there a certain sequence to go by, like at top dead center on intake stroke do certain valves, and on exhaust stroke do certain valves?...thanks,mike.



The HEI won't fit the 3X2 set up (too large) Your Pertronix should work quite well with your engine.
You need to adjust your rockers properly. Rather than trying to print the whole method here, don't you have an engine book (manual) to go from?
It sounds as though you may be better off paying a skilled engine mechanic to do this for you.

[tripower]

The HEI won't fit the 3X2 set up (too large) Your Pertronix should work quite well with your engine.
You need to adjust your rockers properly. Rather than trying to print the whole method here, don't you have an engine book (manual) to go from?
It sounds as though you may be better off paying a skilled engine mechanic to do this for you.

58, I think your about 4 years late on your reply...:rofl :rofl :rofl...I think he figured it out.:takethat

[1958 delivery]

58, I think your about 4 years late on your reply...:rofl :rofl :rofl...I think he figured it out.:takethat

No ****!
I guess some people are slow learners:doh