[grandville455]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by quick67bird:
I will tell you the timing makes a huge difference. In the 1/4 on my first pass the motor laid down in the top of all gears and would barely pull over 5000 rpm on that pass I I ran a 13.86. Long story short I have a fluidamper that has a chevy marks on them and I had my timeing way off. After fixing my timing and jetting the carb up to steps all the way around it went out and ran a 12.55 at 113 spinning the tires at every shift even into third. </div></BLOCKQUOTE>
Wow .dont mean to hijack...But what was the timing before and after?

[quick67bird]

To tell you the truth I dont really know. I know that sounds bad but the front timing housing only has a pointer and the fluidamper has chevy timeing marks on it. The top dead center is right on the damper with the pointer. I ended up timing it by ear and it ran. This year I modified a new cover that has all the timing marks on it so I can at least get a reading.

[Goin' Topless]

Vacuum advance not working? Centrifigal springs too stiff?

Lack of advance early on can make it feel like a dog.

[mikeb]

Sounds kind of like a comp cams magnum 280 cam. I went in the 11's with that cam in a 3600lb bird with a 455.

Your combo doesn't sound that bad at all. It sounds like maybe your mechanical advance isn't working at all, or the cam was installed one tooth off. Something is way wrong.

[Judge not]

Thanks guys. The mechanical advance is all in by 2500 rpm, I lined up the dots on the cam, cam at 6' and crank at 12'. I just don't get this, I am very disappointed

[David Jones]

What kind of timing chain is it?

[Judge not]

David it is a new double roller I bought from Summit, forget the brand.

[Sporter]

Sure sounds like my son's 455 when we installed his XE284 one tooth off. Ran fine but had little power. Was off over .6 and 5 mph at the local 1/8th mile track. Last time I installed a cam after midnight.

[LouisianaGuy]

230/236@50 488/491 cam with an 8.5-1 455....12.83@105
Something is amiss.
Mike

[nightwrencher]

have a 400 with 11 heads and 230/240-112 lca (ported/polished heads) and I've spent a heck of a lot of time towards trying to get better traction. will go sideways through third. haven't raced it yet but my 400 has similar setup and even before the 4.56's. ripped it up with the 2.56 or whatever it had. I disconnected the vaccum advance, ran 16* initial with total 34* (I use 50/50 w/race fuel)
ran aggresive with a th350 with cheapo jegs 22-2400 converter and with 200r4 w/ 2600 stall.

the cam being a tooth off sounds worth checking, but how good did you break in the cam? Is it possible you could have worn the lobes of the cam on break in? I usually do around 25 minutes around 2500 rpm. (to try to prevent overheating, I use clean water and keep the cap off with a running hose)

just my two cents

[grandville455]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by LouisianaGuy:
230/236@50 488/491 cam with an 8.5-1 455....12.83@105
Something is amiss.
Mike </div></BLOCKQUOTE>
Mike rememeber when you were barely running a 100 in the 1/4 ...What have u changed to get it to go 105?..Just curious

[Junkyard Dog]

Try simple stuff first. Advance the total timing 2 degrees at a time and run it full throttle to see if there is any improvement. If your timing marks are off, it won;t matter because you will be setting total timing for maximum performance, not according to some number. If you can time your acceleration run, all the better, but this will at least confirm whether the spark timing is the issue. Make sure to disconnect your vacuum advance during this.

Something is definitely wrong, but try the simple things before tearing the engine apart to check on the cam.

[Judge not]

Hey guys, I just went out and ran the car. I advanced total timing to 32 degrees that puts my initial at 14 degrees, is that ok, also I put the car in gear and stepped on the brakes and gave it gas to see how high I could get the rpms, the cars back tires started spinning at 1500 rpm. Is this lock up rpm too low? Also why does this thing idle so smooth? I can idle it down to 500 rpm, and it does not have rhodes lifters in it.

[Judge not]

Dave I hope I didn't ruin this cam too, that is why I have a new one in there now. The last cam I ruined, but this one I broke in right, GM e.o.s. cam lube and 1/2 turn past 0 lash. 25 minutes at 2000-2500 rpm. I sure hope I didn't trash another one

[David Jones]

A lot of initial advance will smooth out the idle. That cam is really not huge, so I wouldn't expect a real choppy idle. I still think part of the problem is the RPM manifold. They don't really come into their own until further up in the rpm range. Hence the name. What is the lobe separation of the cam? If its 110 to 112 or so that would smooth out the idle also. With 3.55 gears and that cam I'd say a stock converter would work OK. May not be the hot ticket for the strip, but.... Unless its just bad. I'd question the cam installation (Read my latest thread, I'm an expert ) I'd question the intake. I'd question the converter. I'd question the distributor. What springs, is the advance working correctly, weights moving freely etc.

[Junkyard Dog]

Hey, now, wait a second, you said the timing was 32, all in by 2,500 rpm, way back in your first post!

Try 34 and then 36 and even 38 if the situation keeps improving. Maybe even 40. Just keep going until it doesn't improve and then back off a little. Who knows if your timing marks are correct?

14 initial won't hurt anything. The only thing that matters is if you have problems kicking back against the starter when starting. If so, then change your curve (i.e., more difference between initial and mechanical advance, like 20 or 22 rather than your current 18). If you aren't encountering problems on starting, then it is not too much advance.

Since moving your timing (even though you said 32 in both posts) improved the situation, keep it up until you get it to the best setting.

[LouisianaGuy]

That cam is not going to be lumpy is a 455, I keep my car idled at around 750 in gear for town driving and about 850-900 at the track, everyone always comments on it,...they say wow you can barley hear it running and it runs in the 12's and everyone else has a big cam, big converter big tires, and loud exhaust and they are running almost same times as me and are usually in a lighter body...My friends say its got that quiet Cool factor :P Just what i was looking for.
My 455 runs the best at 12 deg initial and 32 all in by 2500, it slows down on mph with 14 degrees.
Mike

[Judge not]

David, you and I had our cams fail at about the same time, I have been following your roller installation blues. I am very happy you got it straightened out The lsa on my cam is 112 1/2 degrees, maybe that is why the idle is so smooth. I checked advance curve with my dial back timing light. The advance starts at about 1000 and is all in by 2500. I have a total timing of 34 deg. set right now. It starts fine when cold but bucks when warm. Also with my last cam I had the performer intake and it was no better. The car pulls hard, I just don't have the tire shredding at will I have to take her to the strip to see what she does in the 1/4. Thanks all for the advice.

[Tart '67]

I think that you could blame it on your neighbor!

[Judge not]

Yeah, he is a skeezer