Timing Problem
Thread Starter
Safety Car
Joined: Jun 2005
Posts: 3,841
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From: Inver Grove Minnesota
Timing Problem
I need to retime my 78 with a HEI Distributor in a L-48. Where would be a good place to start with the vacuum off, and with it on? Also I'm thinking of getting a turn-key crate engine do you guys have any thought on this. Or, I have the chance to get a free 305 that needs a bore and a rebuild. Should I get that and have it bored to 350 and put on performace parts? I think turn-key sounds good because I know that it will work... I've never built an engine before (I'm 17). I'm aiming for about 380-390 horse I was told my stock turbo 400 could take around 400 horse.
Just another Corvette guy
Joined: Feb 1999
Posts: 8,518
Likes: 3,863
From: Palm Springs, CA.
Hi Justin,
You should be safe around 8 degrees with the vacuum advance disconnected.
Stay away from the 305 it's just not worth it. The crate engine is a very good choice for your Vette and the prices are pretty good for what you get.
Good luck,
Greg
You should be safe around 8 degrees with the vacuum advance disconnected.
Stay away from the 305 it's just not worth it. The crate engine is a very good choice for your Vette and the prices are pretty good for what you get.
Good luck,
Greg
Pro
Joined: Jan 2002
Posts: 624
Likes: 0
From: Marietta ga
Originally Posted by JustinD
I need to retime my 78 with a HEI Distributor in a L-48. Where would be a good place to start with the vacuum off, and with it on? Also I'm thinking of getting a turn-key crate engine do you guys have any thought on this. Or, I have the chance to get a free 305 that needs a bore and a rebuild. Should I get that and have it bored to 350 and put on performace parts? I think turn-key sounds good because I know that it will work... I've never built an engine before (I'm 17). I'm aiming for about 380-390 horse I was told my stock turbo 400 could take around 400 horse.
You sound like a good vette owner... already interested in more power
I would stay away from the 305. Some say they belong at the bottom of the sea. They make good low end torque but they die after 4000 RPM. There is also very few after market parts for the 305. Due to the small bore, most aftermarket SBC heads will not fit on a 305. A rebuild on a 305 is going to be a waste of money.
A turn key motor sounds like a great option. You can purchase a 400hp 350ci for not too much these days. I would look into ones that are sold by well known companies or ask forum members for recomendations. I have never bought a turn key motor myself so I could not tell you. Look up old posts on ZZ4 motors.. they are cheap and come for the general.
As for the timming... 8 degrees with the vacuum off and pluged is a good place to start. You can most likely get closer to 14 degrees out of the motor. Remeber to check your total timming too.... very important
Race Director
Joined: Aug 2004
Posts: 10,628
Likes: 132
From: Duvall, WA
Used 350 engines are not real expensive. You can go to a local you-pull-it junkyard and get one for next to nothing. I wouldn't want the 305, and one can't bore it to make it a 350. I enjoy building my own engines, but it sounds like you'd have to do quite a bit of reading before starting that project.
Racer
Joined: Dec 2005
Posts: 344
Likes: 0
From: Washington DC
DONT KNOCK THE 305! That's what I have in my 69.
On second thought, feel free. I didnt put it there and I am going to put a 350 back in when I have the time/money/facilities. 305 is great for what it is, but I cant wait to have that 350 in there.
On second thought, feel free. I didnt put it there and I am going to put a 350 back in when I have the time/money/facilities. 305 is great for what it is, but I cant wait to have that 350 in there.
Race Director
Joined: Aug 2004
Posts: 10,628
Likes: 132
From: Duvall, WA
Originally Posted by Ak. Mal
I thought the 305 and the 350 were the same block design, just different bore and stroke?
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Thread Starter
Safety Car
Joined: Jun 2005
Posts: 3,841
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From: Inver Grove Minnesota
Ok, I'll scrach the 305. I was looking for around 380-400 horse turn key. Are there any recommendations... ZZ4 seem like a good value.
Last edited by JustinD; Apr 5, 2006 at 09:25 PM.
Race Director
Joined: Oct 2000
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From: Kansas City, MO ...I'd like to go fishing and catch a fishstick. That'd be convenient. - Mitch Hedberg
Originally Posted by rcread
The 305 and 350 are both small blocks, but the 305 has bigger water jackets. The bore on the 305 is 3.736 and the 350 is 4". Cylinder wall thickness is about .15" on both engines. If you bored the 305 out to 4", the cylinder walls would be only about .018" thick, and that's not going to work.
Burning Brakes
Joined: Mar 2006
Posts: 750
Likes: 82
From: Bedford IN
I just had a tread about timing my 76'. I ended up at 18 initial timing with vacuum off. With a total timing right at 34 or 35 all in by 2500-2700 rpm. Depending on the springs is going to depend on when you will reach total timing. Good luck. Also go by how good it runs. The more timing that i can trow at mine the better it runs. I also put 10 to 1 comp pistons in mine.
Pro
Joined: Sep 2004
Posts: 595
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From: Boston MA
timing....
Set the total timing to 36 and have it come all the way in by 2500 RPM....
Do NOT set it to 8 degrees initial or by the manufacturer's recommendation unless you have to pass emissions!
Thanks,
Joe
Do NOT set it to 8 degrees initial or by the manufacturer's recommendation unless you have to pass emissions!
Thanks,
Joe
Race Director
Joined: Oct 2000
Posts: 11,891
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From: Kansas City, MO ...I'd like to go fishing and catch a fishstick. That'd be convenient. - Mitch Hedberg
http://www.corvettefaq.com/c3/HowToSetTiming2.doc
The link above to to a paper on how to set timing written by forum member Lars.
The link above to to a paper on how to set timing written by forum member Lars.
Pro
Joined: Sep 2004
Posts: 595
Likes: 0
From: Boston MA
Originally Posted by JustinD
Nope emissions are not a problem. Does my initial timing really matter then, or should I just warm it up and bring it to 2500 rpm and get it to 36?
Thanks,
Joe