Tuning Questions and mufflers - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Jesse 67 c-10 · 06-12-2002, 01:11 PM

I've been moving around on the timing on my 327 to get it running the best, what I'm wondering is, when I advance it more, it picks up a lot better and has more power and throttle response, but just free reving it seems to knock or back fire quite a bit, It also hesitates a quite a bit when I first get on it, after that, holy ****!, but it'll really bog down if I floor it for example on the 2nd to 3rd shift. I can back it off till it runs smoother but it hesitates more then. Any tips? higher octane gas? shood I play with the advance curve a bit too? I have adjustable vacume advance and it's hooked up to the pass side port on my 1406. I'm suspicious about the outer ring on my balancer having slipped, and have just been going by ear, what's the best way to set the timing without a light? I've heard vacume gauge?

Also, I'll soon be puting exaust on my truck 2 1/2" duals, and I want to know some recomends for nice sounding mufflers. I don't want it too loud but not too mellow either. Anyone have a sound recording? your favorites?
Thanks lots for the help!
Jesse

diggin69 · 06-12-2002, 01:52 PM

I had a truck with 2 1/4 straight out the back & I had mufflers off a 69 chevelle I found at a swap meet still in the box...... the chamberd exaust system that you had to order.......they sounded like glass packs mellow around 35 even on the highway they sounded great but when you laid in on it thee would make flow masters run with their tail beetween their legs they sounded good......but the only thing that comes close to them now is turbo tubes......as far as the timingg goes you would be better offf getting a timing light,or see if the timing tab is in the right place if you did not build the engine some people will think they know what they are doing & put the tab bellow the water pump, or on the timing cover & that can throw it out.... then I would start checking everything, cap,wires,plugs,rotor,coil,or control mod., ckeck for vacum leacks, hoses.
I hope this helps you. Diggin 69

zardiw · 06-12-2002, 04:52 PM

If your balancer is going bye bye, GET A NEW ONE RIGHT NOW! Also don't screw around, i.e. buy/borrow a timing light. Check out your carb also and tune it. There's some good info on doing this on the web, I just can't think of where right now. Go to Google.com and do a search.......z

Riptide · 06-12-2002, 05:14 PM

40 series Flowmaster's and that all I have to say about that.

speeddemon · 06-12-2002, 05:15 PM

I have a set of summit fully welded mufflers on my truck. They are kind of a knock off of flowmasters but not as loud. They have a really killer sound while crusing and are around 20 bucks cheaper than flowmasters.

68 with 350 TPI · 06-12-2002, 06:12 PM

I would have to say that a 40 series flowmaster sounds very good

But the hooker areo chamber mufflers sound really good too (very close to a flowmaster but a bit deeper).
BTW the hooker areo chambers do flow a bit better than the flowmasters but I dont think you can go wrong with either as I have used both and love them.

Jesse 67 c-10 · 06-13-2002, 01:08 AM

I guess it sounds worse than it is the way I wrote it, it is more of a running rough than backfiring and knocking. smooths out under power or with less timing. The hesitation is more what I'm trying to fix. Thanks for the concern though! All the ignition stuff is good new stuff, accel dist, cap, coil and wires, platinum plugs, new carb, I don't know where there could be any vacume leaks, I got one of those chome timing tabs, Mr Gasket, it's in the right place, but does anyone know if it would be for the older or newer balancers? I believe the marks are about 8 deg diffenent. My balancer is off a newer engine, but I didn't know about the differences when I bought the tab. This info would help when trying to use the timing light! Also, hows 10 deg initial and 34 total sound for advance numbers? When should all the advance be in by? I have vortech heads and accel ignition. right now it has 87 octane gas, could this be part of the problem too?

Sounds like most people like 40 series flomasters, I just have to figure out exhaust routing. Thanks!
Jesse

zardiw · 06-13-2002, 01:24 AM

10 degrees initial sounds like a lot. Get one of those piston stops that screw into the number one spark plug hole, and find out where EXACTLY TDC is.....z

06-12-2002, 01:11 PM	#1
Jesse 67 c-10 Registered User Join Date: Feb 2000 Location: Edmonton, Alberta, Canada Posts: 599	Tuning Questions and mufflers I've been moving around on the timing on my 327 to get it running the best, what I'm wondering is, when I advance it more, it picks up a lot better and has more power and throttle response, but just free reving it seems to knock or back fire quite a bit, It also hesitates a quite a bit when I first get on it, after that, holy ****!, but it'll really bog down if I floor it for example on the 2nd to 3rd shift. I can back it off till it runs smoother but it hesitates more then. Any tips? higher octane gas? shood I play with the advance curve a bit too? I have adjustable vacume advance and it's hooked up to the pass side port on my 1406. I'm suspicious about the outer ring on my balancer having slipped, and have just been going by ear, what's the best way to set the timing without a light? I've heard vacume gauge? Also, I'll soon be puting exaust on my truck 2 1/2" duals, and I want to know some recomends for nice sounding mufflers. I don't want it too loud but not too mellow either. Anyone have a sound recording? your favorites? Thanks lots for the help! Jesse __________________ Edmonton, Alberta, 67 c-10, Long fleet, front disks, 5 lug rear end, 327 with Vortechs, edlbrock manifold, comp cams XE 256, 600cfm carb. Backed by a getrag 5 speed and 1 piece driveshaft. 1993 Dihatsu Hijet Jumbo cab 4x4, currently converting to battery electric power.

06-12-2002, 01:52 PM	#2
diggin69 Southern but in Ohio!!!! Join Date: Jan 2002 Location: Eaton,Oh. 45320 Posts: 467	I had a truck with 2 1/4 straight out the back & I had mufflers off a 69 chevelle I found at a swap meet still in the box...... the chamberd exaust system that you had to order.......they sounded like glass packs mellow around 35 even on the highway they sounded great but when you laid in on it thee would make flow masters run with their tail beetween their legs they sounded good......but the only thing that comes close to them now is turbo tubes......as far as the timingg goes you would be better offf getting a timing light,or see if the timing tab is in the right place if you did not build the engine some people will think they know what they are doing & put the tab bellow the water pump, or on the timing cover & that can throw it out.... then I would start checking everything, cap,wires,plugs,rotor,coil,or control mod., ckeck for vacum leacks, hoses. I hope this helps you. Diggin 69 __________________ 1969 C/10 3/4 ton 4x4 longbed custom, frame made from a 79 1972 custom-10 half/ton longbed 1980 1/2 ton 4x4 all original 350/350/205 with air Eaton,Oh rebelryder@hotmail.com

06-12-2002, 04:52 PM	#3
zardiw Faster horses, yw, ow, mm Join Date: Apr 2002 Posts: 184	If your balancer is going bye bye, GET A NEW ONE RIGHT NOW! Also don't screw around, i.e. buy/borrow a timing light. Check out your carb also and tune it. There's some good info on doing this on the web, I just can't think of where right now. Go to Google.com and do a search.......z __________________ '73 C20, 383, 3500 leaf springs, 38.5 Mickey Thompson Baja Claws (More ground clearance than an H2 Hummer), Performance Distributor (Tits!!) w/Clear cap (awesome at night), Edelbrock intake+IAS shocks, Tri Y headers, Dr. Gas Xover(for that NASCAR sound).

06-12-2002, 05:14 PM	#4
Riptide Registered User Join Date: Apr 2002 Location: McPherson, KS US Posts: 102	40 series Flowmaster's and that all I have to say about that. __________________ 67 Chevy C10 McPherson, Ks "Remember Don't Sweat the Petty Things, Pet the Sweaty Things"

06-12-2002, 05:15 PM	#5
speeddemon Registered User Join Date: May 2002 Location: lexington,South Carolina Posts: 158	I have a set of summit fully welded mufflers on my truck. They are kind of a knock off of flowmasters but not as loud. They have a really killer sound while crusing and are around 20 bucks cheaper than flowmasters. __________________ 69-C10 LWB 71- fleetside shortbed It's a shame stupidity isn't painful Never play leapfrog with a unicorn

06-12-2002, 06:12 PM	#6
68 with 350 TPI Registered User Join Date: May 2002 Location: Wingate NC Posts: 456	I would have to say that a 40 series flowmaster sounds very good But the hooker areo chamber mufflers sound really good too (very close to a flowmaster but a bit deeper). BTW the hooker areo chambers do flow a bit better than the flowmasters but I dont think you can go wrong with either as I have used both and love them. __________________ Life is good with a 6-71 supercharged 355 in a 72 camaro

06-13-2002, 01:08 AM	#7
Jesse 67 c-10 Registered User Join Date: Feb 2000 Location: Edmonton, Alberta, Canada Posts: 599	I guess it sounds worse than it is the way I wrote it, it is more of a running rough than backfiring and knocking. smooths out under power or with less timing. The hesitation is more what I'm trying to fix. Thanks for the concern though! All the ignition stuff is good new stuff, accel dist, cap, coil and wires, platinum plugs, new carb, I don't know where there could be any vacume leaks, I got one of those chome timing tabs, Mr Gasket, it's in the right place, but does anyone know if it would be for the older or newer balancers? I believe the marks are about 8 deg diffenent. My balancer is off a newer engine, but I didn't know about the differences when I bought the tab. This info would help when trying to use the timing light! Also, hows 10 deg initial and 34 total sound for advance numbers? When should all the advance be in by? I have vortech heads and accel ignition. right now it has 87 octane gas, could this be part of the problem too? Sounds like most people like 40 series flomasters, I just have to figure out exhaust routing. Thanks! Jesse __________________ Edmonton, Alberta, 67 c-10, Long fleet, front disks, 5 lug rear end, 327 with Vortechs, edlbrock manifold, comp cams XE 256, 600cfm carb. Backed by a getrag 5 speed and 1 piece driveshaft. 1993 Dihatsu Hijet Jumbo cab 4x4, currently converting to battery electric power.

06-13-2002, 01:24 AM	#8
zardiw Faster horses, yw, ow, mm Join Date: Apr 2002 Posts: 184	10 degrees initial sounds like a lot. Get one of those piston stops that screw into the number one spark plug hole, and find out where EXACTLY TDC is.....z __________________ '73 C20, 383, 3500 leaf springs, 38.5 Mickey Thompson Baja Claws (More ground clearance than an H2 Hummer), Performance Distributor (Tits!!) w/Clear cap (awesome at night), Edelbrock intake+IAS shocks, Tri Y headers, Dr. Gas Xover(for that NASCAR sound).

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