LT1 to LT4 conversion?
Thread Starter
Le Mans Master
Joined: Dec 2000
Posts: 5,386
Likes: 2
From: San Angelo TX
LT1 to LT4 conversion?
Has anyone had any experience with the LT1-LT4 conversion that is listed on http://www.paceparts.com?
"Our LT1 to LT4 conversion will bring the most out of your factory LT1 engine with bolt on parts. It includes LT4 cylinder heads complete with valves and springs, a beautiful red aluminum LT4 intake manifold, GM Performance Part's HOT cam kit which includes 1.6:1 ratio Bow Tie roller rockers, and all the necessary gaskets to complete the job. We also offer the correct Edelbrock/BBK throttle body assembly to bring the most out of this conversion. This kit is a proven 425+ horsepower increase ! - $2095.00"
is this for real? doesnt the LT4 use larger intake/exhaust valves plus higher compression pistons and would I be better off doing a conversion of this type by peicing it together myself?
"Our LT1 to LT4 conversion will bring the most out of your factory LT1 engine with bolt on parts. It includes LT4 cylinder heads complete with valves and springs, a beautiful red aluminum LT4 intake manifold, GM Performance Part's HOT cam kit which includes 1.6:1 ratio Bow Tie roller rockers, and all the necessary gaskets to complete the job. We also offer the correct Edelbrock/BBK throttle body assembly to bring the most out of this conversion. This kit is a proven 425+ horsepower increase ! - $2095.00"
is this for real? doesnt the LT4 use larger intake/exhaust valves plus higher compression pistons and would I be better off doing a conversion of this type by peicing it together myself?
Team Owner
Joined: Aug 2000
Posts: 40,156
Likes: 45
From: San Pedro CA
Re: LT1 to LT4 conversion? (IcemanZ06)
I don't think the LT4 had more compression. Remember - the LT4 is RATED at only 30 hp more (most of us agree - it is more like 50 more than the LT1!).
There were a number of differences between the LT1 and LT4. The biggest being the cam and the heads. What the differences are, I really don't know.
If they are getting that kind of power, for that $$, it sounds like one helluva great deal! I may want to check that one out!!!
There were a number of differences between the LT1 and LT4. The biggest being the cam and the heads. What the differences are, I really don't know.
If they are getting that kind of power, for that $$, it sounds like one helluva great deal! I may want to check that one out!!!
Burning Brakes
Joined: Apr 2001
Posts: 1,209
Likes: 0
From: Toronto Ontario
St. Jude Donor '13
Re: LT1 to LT4 conversion? (IcemanZ06)
Iceman,
I never compared the purchase to acutally buyuing the stuff seperatly. But I can tell you what i do know.
LT4-If you look around you can get them for 800-1000
LT4 Intake- $200 new from a dealer
LT4 Rockers-$150, they are always for sale on the forum or put up a wtb post
i got mine off the forum for 150
LT4-Don't know value
BBK Tbody-$300 New, 225 used from a forum guy or on ebay
Work it it out, it may be worht. I have always liked putting my own parts and combination together, it has always been cheaper, plus i pick the parts.
The LT4 has 2.00/1.55 valves and they are also hollow stem for reduced weight. THe LT4 runs 10.8:1 CR.
The only thing that pace has over the factory LT4 is the cam. But 425 seems to be pretty generous. I could be wrong.
If your car is an automatic, reconsider the cam, somehting like a ZZ4 cam would be better for the auto's opperating ranges.
Good Luck,
89'
[Modified by 89'Bowtie, 1:07 PM 9/16/2001]
I never compared the purchase to acutally buyuing the stuff seperatly. But I can tell you what i do know.
LT4-If you look around you can get them for 800-1000
LT4 Intake- $200 new from a dealer
LT4 Rockers-$150, they are always for sale on the forum or put up a wtb post
i got mine off the forum for 150
LT4-Don't know value
BBK Tbody-$300 New, 225 used from a forum guy or on ebay
Work it it out, it may be worht. I have always liked putting my own parts and combination together, it has always been cheaper, plus i pick the parts.
The LT4 has 2.00/1.55 valves and they are also hollow stem for reduced weight. THe LT4 runs 10.8:1 CR.
The only thing that pace has over the factory LT4 is the cam. But 425 seems to be pretty generous. I could be wrong.
If your car is an automatic, reconsider the cam, somehting like a ZZ4 cam would be better for the auto's opperating ranges.
Good Luck,
89'
[Modified by 89'Bowtie, 1:07 PM 9/16/2001]
Team Owner
Joined: Nov 1999
Posts: 32,782
Likes: 11
From: Former NCM Drag Racing coordinator, National director Corvette Challenge Spring Hill, Tennessee: Whiting, New Jersey
Cruise-In VI Veteran
Cruise-In VII Veteran
Re: LT1 to LT4 conversion? (IcemanZ06)
I looked at this kit long and hard before I did my car. It has many advantages for some people but for the diehard racer looking for max performance it has to many holes.
Thread Starter
Le Mans Master
Joined: Dec 2000
Posts: 5,386
Likes: 2
From: San Angelo TX
Re: LT1 to LT4 conversion? (89'Bowtie)
Iceman,
LT4-If you look around you can get them for 800-1000
The LT4 has 2.00/1.55 valves and they are also hollow stem for reduced weight. THe LT4 runs 10.8:1 CR.
The only thing that pace has over the factory LT4 is the cam. somehting like a ZZ4 cam would be better for the auto's opperating ranges.
LT4-If you look around you can get them for 800-1000
The LT4 has 2.00/1.55 valves and they are also hollow stem for reduced weight. THe LT4 runs 10.8:1 CR.
The only thing that pace has over the factory LT4 is the cam. somehting like a ZZ4 cam would be better for the auto's opperating ranges.
Lets say I opted against the LT4 heads and ported/polished the LT1 heads (stage I). Would the 1.6RR still clear and also would the LT4 valves fit inside the head or are these dependent on the LT4 head type?
Also, what kind of increase could i expect from a ZZ4 cam? Keep in mind, my car is a daily driver, however I do not mind a little fun :D
[Modified by IcemanZ06, 1:22 PM 9/16/2001]
Burning Brakes
Joined: Apr 2001
Posts: 1,209
Likes: 0
From: Toronto Ontario
St. Jude Donor '13
Re: LT1 to LT4 conversion? (IcemanZ06)
The stock LT1 heads flow about 210cfm. The Sotck LT4 Heads flow 240cfm.
YOu could port the LT1 heads to flow, but the LT4's are better by design. It is all in the design of the actual intack and exhaust runners that helps them to flow more, plus the runners are larger. The LT1 intake ports are 170cc and the LT4's are 195cc. The LT4 have more down the road potential for more porting. You would have to see if your local speed shop can get Lt4 flow figures out of the LT1 for cheaper than buying the heads.
Also, the valves, the LT1 heads would need larger seats to accomodate a larger valve. Without new seat and machinging it is not possible. For the money you are going to spend for bigger vavles in an LT1 heads and the porting sometimes it is cheaper do buy the whole head.
The ZZ4 actually make a little more HP and TQ below 4500rpm. After that the LT4 hot cam starts to come alive and makes more. You can see why.
ZZ4 Cam-208/221 0.474/0.510 @ 0.050
HOT Cam-218/228 0.525/0.525 @ 0.050
That why i say for a daily driver or an auto, a ZZ4 cam is a consideration, unless you race with a auto.
89'
YOu could port the LT1 heads to flow, but the LT4's are better by design. It is all in the design of the actual intack and exhaust runners that helps them to flow more, plus the runners are larger. The LT1 intake ports are 170cc and the LT4's are 195cc. The LT4 have more down the road potential for more porting. You would have to see if your local speed shop can get Lt4 flow figures out of the LT1 for cheaper than buying the heads.
Also, the valves, the LT1 heads would need larger seats to accomodate a larger valve. Without new seat and machinging it is not possible. For the money you are going to spend for bigger vavles in an LT1 heads and the porting sometimes it is cheaper do buy the whole head.
The ZZ4 actually make a little more HP and TQ below 4500rpm. After that the LT4 hot cam starts to come alive and makes more. You can see why.
ZZ4 Cam-208/221 0.474/0.510 @ 0.050
HOT Cam-218/228 0.525/0.525 @ 0.050
That why i say for a daily driver or an auto, a ZZ4 cam is a consideration, unless you race with a auto.
89'
Thread Starter
Le Mans Master
Joined: Dec 2000
Posts: 5,386
Likes: 2
From: San Angelo TX
Re: LT1 to LT4 conversion? (89'Bowtie)
unless you race with a auto.
I have every intention of getting 12s out of my car and doing some autoX on the side here with the Clemson Sports Car Club on the weekends
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Burning Brakes
Joined: Apr 2001
Posts: 1,209
Likes: 0
From: Toronto Ontario
St. Jude Donor '13
Re: LT1 to LT4 conversion? (IcemanZ06)
Ice,
Put it this way.
Higher RPM visits and opperating=LT4 Hot cam
Mid Range RPM opperation=ZZ4 spec style cam
Hight 12's shouldn't be that hard. You may consider a torque converter and 12's are 1/4 mile away.
89'
:flag
Put it this way.
Higher RPM visits and opperating=LT4 Hot cam
Mid Range RPM opperation=ZZ4 spec style cam
Hight 12's shouldn't be that hard. You may consider a torque converter and 12's are 1/4 mile away.
89'
:flag
Melting Slicks
Joined: Jun 2000
Posts: 3,215
Likes: 6
From: Tampa Florida
Re: LT1 to LT4 conversion? (IcemanZ06)
I believe the 425 HP that advertisers use comes from the engine being tested on a engine dyno/gross HP. Chevy High Performance did a build up of a LT1 converted to LT4 with HOT cam and came to this number as well.
Melting Slicks
Joined: Jun 1999
Posts: 2,872
Likes: 3
From: Wilmington NC
Re: LT1 to LT4 conversion? (IcemanZ06)
ice,
i just finished some mods you may be interested in. for less then the lt4 upgrade, i opted for thes mods:
hotcam kit(cam, rockers, springs, shims, etc.. - $522
gaskets/ timing set/ misc. - $250
self ported LT1 heads/ Intake - 15 hours + $59 for SA porting kit
Meziere elec waterpump - $200
hooker ceramic long tube headers - $470 shipped
additional exhaust work - $50
labor - did myself took 3 weeks outside a 5 day a week job and 3 weekends for Everything including head porting
5 angle comp. valve job - $100
new Opti - $237
miscellaneous items - $100
total - $1988
Reading a 12.45@114mph on your time slip after mowing down a N2O stang and learning to all this work yourself.......PRICELESS!! :lol:
just an idea but i feel i got alot of goodies and performance for my $2k and it allowed me to add my pretty wheels and tires on top of it!! with a nice SLP exhaust system. also, i am still getting ready to add gears so perhaps an 11.9xx is in the future after some tuning!! :smash:
good luck,
chris
i just finished some mods you may be interested in. for less then the lt4 upgrade, i opted for thes mods:
hotcam kit(cam, rockers, springs, shims, etc.. - $522
gaskets/ timing set/ misc. - $250
self ported LT1 heads/ Intake - 15 hours + $59 for SA porting kit
Meziere elec waterpump - $200
hooker ceramic long tube headers - $470 shipped
additional exhaust work - $50
labor - did myself took 3 weeks outside a 5 day a week job and 3 weekends for Everything including head porting
5 angle comp. valve job - $100
new Opti - $237
miscellaneous items - $100
total - $1988
Reading a 12.45@114mph on your time slip after mowing down a N2O stang and learning to all this work yourself.......PRICELESS!! :lol:
just an idea but i feel i got alot of goodies and performance for my $2k and it allowed me to add my pretty wheels and tires on top of it!! with a nice SLP exhaust system. also, i am still getting ready to add gears so perhaps an 11.9xx is in the future after some tuning!! :smash:
good luck,
chris
Drifting
Joined: Apr 2000
Posts: 1,803
Likes: 1
From: PA
Re: LT1 to LT4 conversion? (lcvette)
"Built" versions of the LT1 and LT4 motor result in nearly the same output. "More Performance" and "Lingenfelter" offer nearly identical dyno tested LT1 and LT4 packages that use OEM heads and intakes for Emissions certification. The difference is a measily 10 HP, 425 HP LT1 vs 435 HP LT4. Plus, the LT4 requires intake manifold porting and the LT1 does not. Switching to LT4 heads and intake for 10 HP doesn't seem to make economic sense. Plus, the LT4 setup has a narrower, higher RPM powerband that can overstress the LT1 bottom end and result in the spitting of parts. The 425 HP LT1 produces peak HP below the stock LT1 rev limit.
Thread Starter
Le Mans Master
Joined: Dec 2000
Posts: 5,386
Likes: 2
From: San Angelo TX
Re: LT1 to LT4 conversion? (khornet)
Not sure about the LT1 performance numbers but a friend of mine had an LPE 383 L98 and it was killer fast. 1/4 in the mid/upper 11s N/A :D
Would be awesome to see the LT1 equivelent
Would be awesome to see the LT1 equivelent
Le Mans Master
Joined: Aug 1999
Posts: 7,339
Likes: 137
From: WilkesBarre PA
Re: LT1 to LT4 conversion? (khornet)
A good machine shop can put 2.00/1.56 in the LT1 heads with the stock seats. There is enough of a seat there. But it needs larger seats installed for anything bigger.I used the stock LT1,ported with bigger valves in my 95 LT1 6 speed with the Hot cam. The best time was in my sig. If it was in Mack or JPs car it would have went 11's :D
[Modified by RichS, 5:47 PM 9/17/2001]
[Modified by RichS, 5:47 PM 9/17/2001]
Safety Car
Joined: Nov 1999
Posts: 3,891
Likes: 2
From: Houston, TX
Re: LT1 to LT4 conversion? (89'Bowtie)
The stock LT1 heads flow about 210cfm. The Sotck LT4 Heads flow 240cfm.
YOu could port the LT1 heads to flow, but the LT4's are better by design. It is all in the design of the actual intack and exhaust runners that helps them to flow more, plus the runners are larger. The LT1 intake ports are 170cc and the LT4's are 195cc. The LT4 have more down the road potential for more porting. You would have to see if your local speed shop can get Lt4 flow figures out of the LT1 for cheaper than buying the heads.
Also, the valves, the LT1 heads would need larger seats to accomodate a larger valve. Without new seat and machinging it is not possible. For the money you are going to spend for bigger vavles in an LT1 heads and the porting sometimes it is cheaper do buy the whole head.
Instructor
Joined: Aug 2001
Posts: 146
Likes: 0
From: SC
Re: LT1 to LT4 conversion? (IcemanZ06)
Pace's kit is great if you're going to do it yourself. You save some money. If you go someplace like MORE Performance, you get a similar LT4 kit, with a different cam, and all the experience they have for the installation, but it costs more.
From what I've seen, the LT4 kit puts out similar power to a ported LT1 heads kit with the LT4 hot cam. It all depends on what you want and what you're willing to spend! :seeya
From what I've seen, the LT4 kit puts out similar power to a ported LT1 heads kit with the LT4 hot cam. It all depends on what you want and what you're willing to spend! :seeya