LA 318 advice

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Overlap is the greyed out triangle in between. Moving the lobes closer together (tighten lsa) and or increase duration gonna increase that overlap triangle, rough idle.

If you say keep lsa at 108 then decreasing duration will be the only way to reduce overlap which is basically what you want small ish cam on a relatively tight lsa. Earlier intake valve closing point.


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No it won't. As long as he keeps duration down, it will not. If he uses something like 216 @ .050 on a 108, he'll have a barely noticeable idle in a 318. You telling him that is gonna scare him away from what he needs. All slant 6 cams are ground on 108 and 109 LSAs. Do they idle rough stock? No.
 
No it won't. As long as he keeps duration down, it will not. If he uses something like 216 @ .050 on a 108, he'll have a barely noticeable idle in a 318. You telling him that is gonna scare him away from what he needs. All slant 6 cams are ground on 108 and 109 LSAs. Do they idle rough stock? No.
Never said it couldn't have a mild idle on a 108, I said overlap is responsible for rough idle and the two main factors are more duration and tighter lsa, so if you go with a tighter lsa with a smaller duration you get less overlap smoother idle, it depends on the overall overlap not how you accomplish that overlap was my point.
 
Compared to what?
Let me give this a proper reply.

I can’t compare it to anything, I’m not an engine designer, I don’t speak cam-ese.
I’m a heck of a wrench turner and measurement guy.
I don’t give out advice on what works best, etc, I do offer advice on what worked for me.
This is the only engine in my life that I dropped fully dressed, minus the carbs and exhaust manifolds. I loved 100+ miles from the shop and where the project was stored. I said “rebuild it and put it together”.
In the fist 1/2 of my engine building life I seeked advice from older friends, family, etc based on their knowledge and their friends knowledge. Times change, etc and I relied on shops and recomendations, or the speed shops recommendations, on parts to use, I would buy the parts from them, have the machine shop machine it, I’d remeasure everything (mics and dial bore gauges) and put it together.

When those shops closed up the internet was starting to get into full swing. So for the past 20+ years, www I seek information dot com.

So I thought I asked a legitimate question. It was answered and fully explained why to me.

If it sounded like I was questioning, not asking a question, I the he would not have explained it how he did.

If you’ve read all the replies in this thread, you should remember mine. I said @i came to this forum to join and ask advice, I feel I came to the right place@. I started out wanting more compression, I’ve since learned for my goals it’s not necessary, hence why I said I’m going to just make sure the block is square, .020 under the 9.6 blueprint spec by Mopar.

I know it’s a lengthy reply to your question, but also felt it may dispel some future comments (I won’t repeat).
At 63 I think I have a few more projects in me, it’s how I spend my spare time.

Beats hitting the bars, watching TV, etc.
So to sum it up, I can’t compare to anything because I don’t have the knowledge of it to compare.
But I figured the background might give the insight as to why.
When I hung out with guys who bench raced, I listened. I didn’t try to speak of things I didn’t know. :)
 
Let me give this a proper reply.

I can’t compare it to anything, I’m not an engine designer, I don’t speak cam-ese.
I’m a heck of a wrench turner and measurement guy.
I don’t give out advice on what works best, etc, I do offer advice on what worked for me.
This is the only engine in my life that I dropped fully dressed, minus the carbs and exhaust manifolds. I loved 100+ miles from the shop and where the project was stored. I said “rebuild it and put it together”.
In the fist 1/2 of my engine building life I seeked advice from older friends, family, etc based on their knowledge and their friends knowledge. Times change, etc and I relied on shops and recomendations, or the speed shops recommendations, on parts to use, I would buy the parts from them, have the machine shop machine it, I’d remeasure everything (mics and dial bore gauges) and put it together.

When those shops closed up the internet was starting to get into full swing. So for the past 20+ years, www I seek information dot com.

So I thought I asked a legitimate question. It was answered and fully explained why to me.

If it sounded like I was questioning, not asking a question, I the he would not have explained it how he did.

If you’ve read all the replies in this thread, you should remember mine. I said @i came to this forum to join and ask advice, I feel I came to the right place@. I started out wanting more compression, I’ve since learned for my goals it’s not necessary, hence why I said I’m going to just make sure the block is square, .020 under the 9.6 blueprint spec by Mopar.

I know it’s a lengthy reply to your question, but also felt it may dispel some future comments (I won’t repeat).
At 63 I think I have a few more projects in me, it’s how I spend my spare time.

Beats hitting the bars, watching TV, etc.
So to sum it up, I can’t compare to anything because I don’t have the knowledge of it to compare.
But I figured the background might give the insight as to why.
When I hung out with guys who bench raced, I listened. I didn’t try to speak of things I didn’t know. :)
I was simply trying to figure out what your basis of comparison was. That was all, really.
 
I was simply trying to figure out what your basis of comparison was. That was all, really.
Sorry, hope you didn’t take offense, as that wasn’t my intention.
There were some replies made by some I think just read my original post, skimmed through, missed some key items and commented.
No matter.
But I thought a bit of a background (maybe should have been my introduction post instead. ;). Would let those know it’s not my first, hopefully not my last engine to put back together.

Not sure I mentioned it before, on the forum I usually go to it was recommended to to me to join and ask here.
See in my googling I was here 10/12 times.
What prompted me to sign up, was due to my sig line that I was looking for a dual plane intake for a 318.
I know about the Streetmaster from SBC times, my friend had one on a 283 back in the day. Worked well for him.
A member on that form posted a link here, so I joined to purchase the intake. Killed two birds with one stone.
But used some of the info from that forum, in the opening post here.
I didn’t get the “been there..” advice like I have here, plus I also got the explanations and reasons why as well.

Hence 8:1 SCR now, I’ll die grind on the heads like I’ve done in the past (remind me to stay away from the seats please) and put it together when the shop does what I ask, just a square deck at 9.58 and be back in business.
 
Sorry, hope you didn’t take offense, as that wasn’t my intention.
There were some replies made by some I think just read my original post, skimmed through, missed some key items and commented.
No matter.
But I thought a bit of a background (maybe should have been my introduction post instead. ;). Would let those know it’s not my first, hopefully not my last engine to put back together.

Not sure I mentioned it before, on the forum I usually go to it was recommended to to me to join and ask here.
See in my googling I was here 10/12 times.
What prompted me to sign up, was due to my sig line that I was looking for a dual plane intake for a 318.
I know about the Streetmaster from SBC times, my friend had one on a 283 back in the day. Worked well for him.
A member on that form posted a link here, so I joined to purchase the intake. Killed two birds with one stone.
But used some of the info from that forum, in the opening post here.
I didn’t get the “been there..” advice like I have here, plus I also got the explanations and reasons why as well.

Hence 8:1 SCR now, I’ll die grind on the heads like I’ve done in the past (remind me to stay away from the seats please) and put it together when the shop does what I ask, just a square deck at 9.58 and be back in business.
Hardly. You're makin way more of this than necessary. lol
 
There were some replies made by some I think just read my original post, skimmed through, missed some key items and commented.

welcome to FABO...

.... I was looking for a dual plane intake for a 318.
I know about the Streetmaster... so I joined to purchase the intake.

if you were looking for a dual plane, why did you buy the streetmaster? on familiarity alone? i mean, it's fine for what it sounds like you're looking to do. but i just find the choice interesting.
 
welcome to FABO...



if you were looking for a dual plane, why did you buy the streetmaster? on familiarity alone? i mean, it's fine for what it sounds like you're looking to do. but i just find the choice interesting.
It's one of the worst ones IMO. I like the Street Dominator about the best for these kinda builds. While it's a single plane, I don't have to tell YOU that it loses nothing on the bottom end. It's just a great older intake. The plenum on the Streetmaster is very restrictive.
 
And the Streetmaster is a single plane, as you can see. Look at the difference. LOL
STREETMASTER.jpg


STREET DOMINATOR.jpg
 
Well, a few reasons on the Streetmaster. One
The small ports worked well in the days before the performer dual
Plane was out.
The second for the era I want this engine to look like, it’s a better fit.
Another is since I lowered my original expectations and and thoughts on the engine, 5k max
rpm will be just fine.

Unless I can breed the street dominator I have left over from a Ford 302 I did years ago;)
 
Problem is everyone on line is ok with spending your money. knowing what overhaul rebuild and balance and blueprint means helps when making decisions. People tend to mix the three and go for "balance and blueprint" as a "rebuild" there is absolutely no reason to spend 6 grand on an LA 318 rebuild etc.
 
It's one of the worst ones IMO. I like the Street Dominator about the best for these kinda builds. While it's a single plane, I don't have to tell YOU that it loses nothing on the bottom end. It's just a great older intake. The plenum on the Streetmaster is very restrictive.
everything has its place even the torker I...

(which is funny, because the streetmaster kinda looks torker I esque, and the torker II looks street dominator adjacent... but i digress...)

anyway, i like a streetmaster fine for a small carb and low compression motor that doesn't see the high side of 5K and you're on a budget. the street dom is probably a better overall choice and you can run a spread bore on it. you don't give up anything on the bottom end, and the small ports are matchy-matchy. but if it's all about budget, a stock dual plane 4bbl will absolutely run with it till 5 and change.

really it can come down to visual appeal with some builds like this. and the stock dual plane or a perfomer don't really move the needle for a lot of folks.
 
everything has its place even the torker I...

(which is funny, because the streetmaster kinda looks torker I esque, and the torker II looks street dominator adjacent... but i digress...)

anyway, i like a streetmaster fine for a small carb and low compression motor that doesn't see the high side of 5K and you're on a budget. the street dom is probably a better overall choice and you can run a spread bore on it. you don't give up anything on the bottom end, and the small ports are matchy-matchy. but if it's all about budget, a stock dual plane 4bbl will absolutely run with it till 5 and change.

really it can come down to visual appeal with some builds like this. and the stock dual plane or a perfomer don't really move the needle for a lot of folks.
I love my Street Dominator on my Ford 400. It'll slap pull the snot outta your nose.
 
Well, a few reasons on the Streetmaster. One
The small ports worked well in the days before the performer dual
Plane was out.
The second for the era I want this engine to look like, it’s a better fit.
Another is since I lowered my original expectations and and thoughts on the engine, 5k max
rpm will be just fine.

Unless I can breed the street dominator I have left over from a Ford 302 I did years ago;)
speaking of spending other people's money... you know what would look absolutely trick and be kinda period correct? an LD4B!
 
And I see people say all the time, "The Streetmaster is good for keeping velocity up". To them I say, "Guess what, sparky? That's not the intake's job, it's the heads' job. The heads don't need a cork before them. They ARE the controlling restriction.
 
Well, a few reasons on the Streetmaster. One
The small ports worked well in the days before the performer dual
Plane was out.
The second for the era I want this engine to look like, it’s a better fit.
Another is since I lowered my original expectations and and thoughts on the engine, 5k max
rpm will be just fine.

Unless I can breed the street dominator I have left over from a Ford 302 I did years ago;)
Hay, if you got it, run it! It's better than no intake.
 
everything has its place even the torker I...

(which is funny, because the streetmaster kinda looks torker I esque, and the torker II looks street dominator adjacent... but i digress...)

anyway, i like a streetmaster fine for a small carb and low compression motor that doesn't see the high side of 5K and you're on a budget. the street dom is probably a better overall choice and you can run a spread bore on it. you don't give up anything on the bottom end, and the small ports are matchy-matchy. but if it's all about budget, a stock dual plane 4bbl will absolutely run with it till 5 and change.

really it can come down to visual appeal with some builds like this. and the stock dual plane or a perfomer don't really move the needle for a lot of folks.
I am pretty sure I had the small spread bore holly on the SD I have. But I done recall the size of it, or the square bore one I have that I can’t recall why I have it.
I’ll still hang onto the one I don’t use and the 302 SD intake, I have a 302 in a shed out back, just don’t have a need to use it now for anything.
Plus I don’t look at it everyday. Easy to leave it where it’s at.
The Torker, brings back memories of my 454. I used a torker 2 on it, only thing that I liked about it the carburetor sat at an angle. Dang thing didn’t come alive until it was time to shift.
Swapped it to a buddy for a performer 2? I think it was called, and he used it on his boat.
One piece of advice (the torker) I never should have taken. Well, probably others, that one sticks out. :)
 
I am pretty sure I had the small spread bore holly on the SD I have. But I done recall the size of it, or the square bore one I have that I can’t recall why I have it.
I’ll still hang onto the one I don’t use and the 302 SD intake, I have a 302 in a shed out back, just don’t have a need to use it now for anything.
Plus I don’t look at it everyday. Easy to leave it where it’s at.
The Torker, brings back memories of my 454. I used a torker 2 on it, only thing that I liked about it the carburetor sat at an angle. Dang thing didn’t come alive until it was time to shift.
Swapped it to a buddy for a performer 2? I think it was called, and he used it on his boat.
One piece of advice (the torker) I never should have taken. Well, probably others, that one sticks out. :)
The Torker2 is a pretty good piece.
 
The Torker2 is a pretty good piece.
Well, for a higher winding BBC than mine was/is.
It’s an LS5 from a 70 Vette. About all in and done at 5500.
I can say it was coming on around 3/3.5. Up to then not a lot of difference than the factory cast iron intake.
Now to add, I ran 3.07’s in the ‘57 at the time. It matched up well with what the Vette came with.
But off idle was a a game change with the Performer vs it, and since I never stretched the engine, it was fine for me.
Usually went to 2nd at around 5500-5800.
 
Well, for a higher winding BBC than mine was/is.
It’s an LS5 from a 70 Vette. About all in and done at 5500.
I can say it was coming on around 3/3.5. Up to then not a lot of difference than the factory cast iron intake.
Now to add, I ran 3.07’s in the ‘57 at the time. It matched up well with what the Vette came with.
But off idle was a a game change with the Performer vs it, and since I never stretched the engine, it was fine for me.
Usually went to 2nd at around 5500-5800.
I'm very familiar with that engine. I have a friend I've known all my life with a 70 SS454 Chevelle LS5 car he bought new. I've done quite a bit of restoration work to that car.
 
I'm very familiar with that engine. I have a friend I've known all my life with a 70 SS454 Chevelle LS5 car he bought new. I've done quite a bit of restoration work to that car.
I think maybe two differences between the Chevrolet and the Vette. One I’ll ask about, because I don’t really know.

Does his have factory style short cast iron exhaust manifolds?

One I do know about, no way the heads of the General were going to not let the Vette have a higher HO rating.
You know that as well as I do!
 
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