timing questions
Old Pro Solo Guy
Joined: Dec 2017
Posts: 8,043
Likes: 4,397
From: Marlton NJ
Nope!
It's not a truck engine!
It is one of the best racing engines Chevy ever made.
It was the "King of the hill"
They were all over the dragstrips here in the US for decades, and some still are.
An XCH LS7 is just a 454 version of an L88. And stronger.
I guess he could not find LS7 dash decals. LOL (They never made any)
That Octane sticker came on the console on a real L88, and you can still buy them.
103+95 /2 = 99 Octane my method. or 103 Octane RON your way.
It needs just a little better gas than my LT-1 did.
Beautiful car!
And great engine.
And a real beast.
Well bought.
That was considered the "hoy grail" big block to get, for like 35 years.
Likely 560HP / 560 TQ.
It's not a truck engine!
It is one of the best racing engines Chevy ever made.
It was the "King of the hill"
They were all over the dragstrips here in the US for decades, and some still are.
An XCH LS7 is just a 454 version of an L88. And stronger.
I guess he could not find LS7 dash decals. LOL (They never made any)
That Octane sticker came on the console on a real L88, and you can still buy them.
103+95 /2 = 99 Octane my method. or 103 Octane RON your way.
It needs just a little better gas than my LT-1 did.
Beautiful car!
And great engine.
And a real beast.
Well bought.
That was considered the "hoy grail" big block to get, for like 35 years.
Likely 560HP / 560 TQ.
Last edited by leigh1322; Oct 6, 2024 at 10:50 PM.
Race Director
Joined: Nov 2006
Posts: 13,195
Likes: 7,795
From: Sunshine Coast, Queensland, Australia
2025 C3 of the Year Finalist - Modified
2024 C3 of the Year Finalist- Modified
2022 C3 of the Year Finalist - Modified
Cruise-In VIII Veteran
I'll just add to this, as per the fuel.
As a American who moved to Oz with my Corvette.
If anything, the fuel over here is better. The numbering system is different, true enough. But we don't have the alcohol problem here in Oz that they have in the states. Getting good fuel without alcohol in it is easy here. Problem is, our 98, which is more than fine for most of us. Still isn't good enough for this race engine. What about Av gas? (Aviation fuel) What is the octane on that?
As a American who moved to Oz with my Corvette.
If anything, the fuel over here is better. The numbering system is different, true enough. But we don't have the alcohol problem here in Oz that they have in the states. Getting good fuel without alcohol in it is easy here. Problem is, our 98, which is more than fine for most of us. Still isn't good enough for this race engine. What about Av gas? (Aviation fuel) What is the octane on that?
Old Pro Solo Guy
Joined: Dec 2017
Posts: 8,043
Likes: 4,397
From: Marlton NJ
And we would all love to hear that LS7 grumble!
You just don't hear that much anymore.
Any chance you can post a video with sound?
The way to do a video on this forum, is to post it to Youtube first, and then just copy & paste the link here.
It'll show as soon as you save the post.
That would be like candy to us car junkies!
The Holy Grail of Big Blocks!
With sidepipes no less.
Last edited by leigh1322; Oct 8, 2024 at 08:18 PM.
Team Owner
Joined: Jan 2007
Posts: 53,648
Likes: 878
From: Southern Cal Ca
St. Jude Donor '22
wow, quite a motor. 
av gas is 110 in us octane.
problem is it doesn't really act like car gas and some places won't allow direct av gas to car.
a blend of the 2 is useable.
leigh covered your options.
good luck
av gas is 110 in us octane.
problem is it doesn't really act like car gas and some places won't allow direct av gas to car.
a blend of the 2 is useable.
leigh covered your options.
good luck
Instructor
Joined: Dec 2022
Posts: 156
Likes: 97
From: Virginia
I have had a couple of race motors with big cams. I locked the distributors for fixed timing @ 34°.
You can purchase an after market distributor that has the feature.
They have some great octane boosters available now. I hope they are available for purchase too you. The company is called Race Gas.
https://race-gas.com
Here is something I found online that explains locked timing.
99% of the OEM motors do not require locked out timing cause the OEM factory cams don't have the duration or overlap that would require it.
A 1969 427 L88 corvette motor (264°-273° duration @.050" cam) with automatic trans is a example of a OEM (one of the exceptions) that definatly can and will benefit from locked out timing.
With big cams like this one manifold vacuum drops when idleing in gear which take the idle spark advance with it if/when you depend on vac advance and quick mech advance curve to get the required idle timing.
The (manifold vacuum dependant) timing drops as soon as you put it in gear. The timing drops off as soon as you punch the throttle, right when you need the advance. The engine loads up from lack of idle timing and flairs up when you go from in gear to neutral cause the vac advance fluctuates wildy.
The engine will heat up from lack of idle timing. The power valve fluctuates at idle creating a over rich idle and killing the plugs.
This was one of the few cars factory offered with suck a radical cam and auto trans.
You can purchase an after market distributor that has the feature.
They have some great octane boosters available now. I hope they are available for purchase too you. The company is called Race Gas.
https://race-gas.com
Here is something I found online that explains locked timing.
99% of the OEM motors do not require locked out timing cause the OEM factory cams don't have the duration or overlap that would require it.
A 1969 427 L88 corvette motor (264°-273° duration @.050" cam) with automatic trans is a example of a OEM (one of the exceptions) that definatly can and will benefit from locked out timing.
With big cams like this one manifold vacuum drops when idleing in gear which take the idle spark advance with it if/when you depend on vac advance and quick mech advance curve to get the required idle timing.
The (manifold vacuum dependant) timing drops as soon as you put it in gear. The timing drops off as soon as you punch the throttle, right when you need the advance. The engine loads up from lack of idle timing and flairs up when you go from in gear to neutral cause the vac advance fluctuates wildy.
The engine will heat up from lack of idle timing. The power valve fluctuates at idle creating a over rich idle and killing the plugs.
This was one of the few cars factory offered with suck a radical cam and auto trans.
Old Pro Solo Guy
Joined: Dec 2017
Posts: 8,043
Likes: 4,397
From: Marlton NJ
Very true automatic cars can have this problem. Because of that 200 rpm drop when you put it in gear.
But the OP has a manual.
Many bracket race drag cars with cams this wild or wilder do this, but most are autos.
But some manual trans cars do this as well.
Starting is very difficult unless you have a 20* timing retard during start only.
The retarded spark timing can either be automatic at <300 rpm, or with a manual switch.
It is more complicated, and will still not street drive with a manual as well as a normal curve with vac can setup.
I have read about Race Gas but have no experience with it.
Does anyone here?
It might work well as it seems the OP needs about a 6-7 pt Octane Boost.
93 to 99 our Octane Method
98 to 104 RON Method
But the OP has a manual.
Many bracket race drag cars with cams this wild or wilder do this, but most are autos.
But some manual trans cars do this as well.
Starting is very difficult unless you have a 20* timing retard during start only.
The retarded spark timing can either be automatic at <300 rpm, or with a manual switch.
It is more complicated, and will still not street drive with a manual as well as a normal curve with vac can setup.
I have read about Race Gas but have no experience with it.
Does anyone here?
It might work well as it seems the OP needs about a 6-7 pt Octane Boost.
93 to 99 our Octane Method
98 to 104 RON Method
Last edited by leigh1322; Oct 9, 2024 at 11:14 PM.
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