Boring vs Small Cam for Power & Maintaining Gas Milage

[TheKodiak]

I have a stock 5.7 LT1, with 6:1 roller rocker upgrade. Right now I'm still on the fence about swapping my ECM. I would like more power, and ideally, a 373 would be nice. My concern is correcting the computer to accept the changes. For a noob, am I better off just adding an LT4 Hot cam or a Lingenfelter cam to start off with? Or would going the route of 373 be just as simple to tune? I would also like to retain the current gas mileage, and I understand that I have to sacrifice some fuel for the more power. Which is fine, I just don't want to fill it up every time I go around the block lol. Thanks

[LeMarky Dissod]

I have a stock 5.7 LT1, with 1.6:1 roller rocker upgrade. Right now I'm still on the fence about swapping my ECM.
I would like more power, and ideally, 3.73 would be nice. My concern is correcting the computer to accept the changes.
For a noob, am I better off just adding an LT4 Hot cam or a Lingenfelter cam to start off with? Or would going the route of 3.73 be just as simple to tune?
I would also like to retain the current gas mileage, and I understand that I have to sacrifice some fuel for the more power.
Which is fine, I just don't want to fill it up every time I go around the block.

Even with steveo's $EEhack helping to sort out air fuel and spark table corrections, it takes about five minutes to change the speedo constants for 3.73.
Regardless of experience, 3.73 is WAY simpler and quicker to do, tune-wise - plus it takes some of the strain off the 4L60E.

Your metro / urban MpG will probably IMPROVE.
Once you learn how to tailor your shift tables and keep the TCC locked in 3rd and 4th some more, you might get back some highway MpG too.

Either way, you're gonna want to use steveo's $EEhack to fine-tune your air fuel and spark eventually.

[TheKodiak]

My fault. I meant 383...

Even with steveo's $EEhack helping to sort out air fuel and spark table corrections, it takes about five minutes to change the speedo constants for 3.73.
Regardless of experience, 3.73 is WAY simpler and quicker to do, tune-wise - plus it takes some of the strain off the 4L60E.

Your metro / urban MpG will probably IMPROVE.
Once you learn how to tailor your shift tables and keep the TCC locked in 3rd and 4th some more, you might get back some highway MpG too.

Either way, you're gonna want to use steveo's $EEhack to fine-tune your air fuel and spark eventually.

[1project2many]

I realize you asked about cam and displacement changes, but your typo really brings up a good point. If you're just looking for more scoot, a gear swap could make a real improvement for relatively low expense and work. Cam swap is the second least amount of work but getting the right cam means making sure the vehicle and cam will work well together. Engine displacement increase has the potential for the largest gain at the highest cost and with the most labor.

[LeMarky Dissod]

Since it's a 'vette (instead of an F- B- or D-body) 3.27 or 3.45 rear axle would be advised over 3.73 unless you have very lofty performance goals to be measured in fractions of a second.
Regardless of cam or displacement, 3.27 or 3.45 are very strongly advised, but even more so if you do any engine upgrades.

You already have 1.6 (roller?) rockers. There are many other cams out there besides the LT4 HotCam. I'd be surprised if there was only one Lingenfelter cam.
Lloyd Elliott, Advanced Induction, and Air Flow Research come to mind as having solid reputations for over a decade with the IronBlock LT1 / LT4 performance crowd.
Whatever cam you install, know that most cams entail choosing a torque converter with a higher stall RpM, and upgrading the transmission cooler.
You may also be interested in upgrading the heads at that point.

By now - certainly before even considering installing a 6.3L engine - hopefully you will have upgraded the 4L60E to withstand more torque and RpM.

A decently spec'd and constructed 6.3L engine will likely cost at least 2.5x as much as a cam & heads package.

Tuning for a cam, is far easier than tuning for a 6.3L engine - definitely doable though.

[TheKodiak]

I've been out of the performance scene for over 20 yrs. Back when I had my first vette. Gearing was the way to go, for quick performance, at a great price. At this point almost everything is new. But you're correct about a budget friendly bolt-on, and it seems that would be a solid start. Followed by a cam.

I realize you asked about cam and displacement changes, but your typo really brings up a good point. If you're just looking for more scoot, a gear swap could make a real improvement for relatively low expense and work. Cam swap is the second least amount of work but getting the right cam means making sure the vehicle and cam will work well together. Engine displacement increase has the potential for the largest gain at the highest cost and with the most labor.

[TheKodiak]

I agree, there's a lot of cams out there. But I don't know how to select a cam; duration, lift, and lobe is all greek to me. I selected those because I know how they sound, and they're not too aggressive... IMO. And like you stated, I would have to match the stall converter to the cam. Which is ok. I came across Lloyd Elliott, and I really like the packages there. I would like to "build" my tranny. Maybe stage 2??? But I would also like to retain my smooth shifting. After all, my daughter will be driving it around too. I'm glad you brought up matching the cam with TC. Lets see if I remember correctly. But to match them up, you simply get the cam idle preference, and match it to the stall of the TC? Thanks

Since it's a 'vette (instead of an F- B- or D-body) 3.27 or 3.45 rear axle would be advised over 3.73 unless you have very lofty performance goals to be measured in fractions of a second.
Regardless of cam or displacement, 3.27 or 3.45 are very strongly advised, but even more so if you do any engine upgrades.

You already have 1.6 (roller?) rockers. There are many other cams out there besides the LT4 HotCam. I'd be surprised if there was only one Lingenfelter cam.
Lloyd Elliott, Advanced Induction, and Air Flow Research come to mind as having solid reputations for over a decade with the IronBlock LT1 / LT4 performance crowd.
Whatever cam you install, know that most cams entail choosing a torque converter with a higher stall RpM, and upgrading the transmission cooler.
You may also be interested in upgrading the heads at that point.

By now - certainly before even considering installing a 6.3L engine - hopefully you will have upgraded the 4L60E to withstand more torque and RpM.

A decently spec'd and constructed 6.3L engine will likely cost at least 2.5x as much as a cam & heads package.

Tuning for a cam, is far easier than tuning for a 6.3L engine - definitely doable though.

[LeMarky Dissod]

I agree, there's a lot of cams out there. But I don't know how to select a cam; duration, lift, and lobe is all greek to me. I selected those because I know how they sound, and they're not too aggressive... IMO. And like you stated, I would have to match the stall converter to the cam. Which is ok. I came across Lloyd Elliott, and I really like the packages there. I would like to "build" my tranny. Maybe stage 2??? But I would also like to retain my smooth shifting. After all, my daughter will be driving it around too. I'm glad you brought up matching the cam with TC. Lets see if I remember correctly. But to match them up, you simply get the cam idle preference, and match it to the stall of the TC? Thanks

The names I cited previously are respected by the IronBlock LT1 / LT4 performance community precisely because if you ask them these questions they will help you select a package to your tastes.

That said ...
How a cam sounds also has something to do with tuning of not only the .bin file, but of the exhaust as well.
It can get pretty complex if you let it, especially if you try too hard to be an original.

From having been a contributing member of The B-body Impala SS Forum for over a decade:
3.27 if most of your miles are highway.
3.45 if most of your miles are very 'hilly', metro/urban/city, and/or you must measure performance improvements by fractions of a second.
This applies even if you have no other performance plans.

(Improve tires / brakes / steering / suspension! Yes, it's a tuning forum, but these get overlooked far too often.)

I am not sure if GM's OE catback exhaust system has any restrictive parts. If so, improve those.
That plus a decent cold air intake and the 1.6:1 (roller?) rockers will enhance each other and any further mods you'll do later.
Both performance AND MpGs can already be improved by fine-tuning at this beginner state of mods.

If you reach this state, and find yourself wanting more, shop around for headers.
Studying this subject will prepare you for whether or not you want a heads-cam package.

A mere cam meant to work with the OE heads and 1.6 (roller?) rockers may or may NOT entail:
you should already have had headers by now
larger throttle body (better to re-bore yours or another OE, than to buy aftermarket)
larger fuel injectors (there are larger GM injectors that, compared to OE, have better low pulsewidth performance / better MpG potential, plus spec'd to handle ethanol)
a high-RpM-stall torque converter and ATF cooler

A Heads-&-cam package WILL entail:
you should already have had headers by now
larger throttle body (better to re-bore yours or another OE, than to buy aftermarket)
larger fuel injectors (there are larger GM injectors that, compared to OE, have better low pulsewidth performance / better MpG potential, plus spec'd to handle ethanol)
a high-RpM-stall torque converter and ATF cooler

[TheKodiak]

(Improve tires / brakes / steering / suspension! Yes, it's a tuning forum, but these get overlooked far too often.)

I couldn't agree with you more

I am not sure if GM's OE catback exhaust system has any restrictive parts. If so, improve those.
That plus a decent cold air intake and the 1.6:1 (roller?) rockers will enhance each other and any further mods you'll do later.
Both performance AND MpGs can already be improved by fine-tuning at this beginner state of mods.)

Yes, they're Comp Cams Roller Rockers 1.6:1. Now I'm wondering if the cam has already been replaced, or more work was done to it. Wasn't the OE LT1 cam hydraulic? The exhaust only has the two pre-cats installed. The center cat and mufflers have been removed, while an x-pipe has been installed. Basically straight pipe from the pre-cats.

(If you reach this state, and find yourself wanting more, shop around for headers.
Studying this subject will prepare you for whether or not you want a heads-cam package.

A mere cam meant to work with the OE heads and 1.6 (roller?) rockers may or may NOT entail:
you should already have had headers by now
larger throttle body (better to re-bore yours or another OE, than to buy aftermarket)
larger fuel injectors (there are larger GM injectors that, compared to OE, have better low pulsewidth performance / better MpG potential, plus spec'd to handle ethanol)
a high-RpM-stall torque converter and ATF cooler

A Heads-&-cam package WILL entail:
you should already have had headers by now
larger throttle body (better to re-bore yours or another OE, than to buy aftermarket)
larger fuel injectors (there are larger GM injectors that, compared to OE, have better low pulsewidth performance / better MpG potential, plus spec'd to handle ethanol)
a high-RpM-stall torque converter and ATF cooler

Since you mentioned it, I forgot it does have an Edlebrock BBK 52mm TB, and a K&N. But that's about it. As for headers, I want to go with shorty headers, I believe from hooker.

Based on the intel I've gotten. The overall bang for the buck is headers and the rear gearing upgrade, followed by a cam. And building it up from there... Am I tracking??? I believe building a stroker with my limited resources would set me up for failure. You guys have been great! I really appreciate everyones' 2cents

[LeMarky Dissod]

Yes, they're Comp Cams Roller Rockers 1.6:1. Now I'm wondering if the cam has already been replaced, or more work was done to it.
Wasn't the OE LT1 cam hydraulic? The exhaust only has the two pre-cats installed. The center cat and mufflers have been removed, while an x-pipe has been installed.
Basically straight pipe from the pre-cats.

The OE cam is a hydraulic roller, yes.
There are 2.5" in-&-out mufflers out there that pose very little restriction, if any.

Since you mentioned it, I forgot it does have an Edelbrock BBK 52mm TB, and a K&N. But that's about it. As for headers, I want to go with shorty headers, I believe from hooker.

Based on the intel I've gotten. The overall bang for the buck is headers and the rear gearing upgrade, followed by a cam.

There are aftermarket filters out there that both outflow AND outfilter K&N. I get sad every time an LT1 wears out.
GM never stopped making brand new L31s, but they stopped making new LT1s in the early 2000s. Don't forget that.

My experience with Hooker shorty headers bears out like the Impala SS Forum's experience with them.
They are technically mid-length headers that add a few hundred RpM up top, but they'll never be worth anywhere near as much power as headers that push the catalytic converters further back.

Warning:
In my case, I had to re-route and customize AC lines and heater hoses. My first and second attempts were unsuccessful.
There's a reason why the ISSF calls them cookers: in their un-coated, unfinished, raw state, anything too close to them will be served up well-done.
Since I could not even afford to coat them, my third attempt at re-routing things was successful only because I also added heat shielding.
Among other things, I learned that you wrap everything ELSE, EXCEPT headers.

Long story short, I regret Hooker Headers. Caprices have lots more room underhood than 'vettes, and I still was forced to replace AND reroute AND and heat-shield anything and everything you can think of that can burn or crack or become brittle with exposure to too much heat.

If I could do it over again, I'd rather spend every dime and moment on longer, COATED headers.

... And building it up from there. Am I tracking??? I believe building a stroker with my limited resources would set me up for failure.
You guys have been great! I really appreciate everyone's 2cents.

You're welcome.