Brother Al
I'm Awesome
Hello All, Im still slowly progressing on my '92 Z71 Project, but am thinking about shifting gears on my engine plans ang going with a relatively stock LT1 w/ cast iron heads. (B-Body-Gen II SBC and No, Im Not Going LSX, so please dont post things about LS engines, I dont care).
I tried finding posts about this swap, but the search engine here seems to not like "LT1" as part of the query... It gives me a lot of completely unrelated posts.
Who here has done an LT1 swap?
What did you do for TC control?
Originally, I was going with a new GM ZZ4 shortblock, Vortec heads, and adding a 3rd Gen F-body TPI (Edelbrock vortec tpi intake)... all in the quest for a nice torque curve. (ZZ4 is now discontinued as well)
I Prefer to use readily available parts from the GM parts bin, whenever possible. GM had to engineer parts to last through at least their warranty period of 3-5 years... Aftermarket stuff is usually 90 days to a year or two at best. My experience is that much of the aftermarket stuff out there is reliable at being unreliable, fits...kinda-sorta-with help from a die grinder, and when the part fails, you are left stranded on the side of the road, hundreds of miles from home because no one has it in stock (special order), or ....its a long discontinued product that initially required you to fundamentally change the way GM designed it, so much so, that no stock parts can save you unless you can find everything last GM part you tossed into the trash heap.
Anyway, here's my reasoning.
#1.) TBI sucks... it does the job, but its pretty damn inefficient when compared to a properly-tuned Q-jet or direct injection systems... GM used it because it was very cheap to make... A hunk of machined cast aluminum, some vacuum ports, 2 injectors, a throttle A/F blade, and few sensors... really not complicated in any way.
#2.) The truck variant of the LO5 is doggy; 1992 LO5 C/K variant was rated at 210hp and 300ftlbs/tq. The TBI is what it is, swirl port heads just plain suck, and it lacks the roller valvetrain GM added to passenger car SBCs in 1987.
#3.) The LT1, was an amazing leap in performance. The '94-'95 B-Body LT1 was rated @ 260hp and 330 ftlbs/tq, plus the Caprice curb weight is very similar to a K1500 ext/shortbed. The B-Body LT1 iron heads flow exceptionally well & GM used them as the basis for the L31 Vortec design. The LT1 TPI plenum was a step up from the smaller '85-'92 TPI layout. Both develop healthy, broad, low-end torque curves, which is great for towing. Both engines were mated to the 4L60E (700R4E) so stock wiring can be retained and no fitment issues. Power steering will need to be looked at because the B-Body LT1 used a very undersized PS reservoir & pump for the car's size and weight, so it has failure issues when worked hard...
FYI:
The Optispark can be an expensive PITA... especially if you use aftermarket Opti's which have generic optical sensors. (Cant beat the original GM-Mitsubishi one)... the later design, "vented" Opti is pretty reliable, so long as you check the vent line for damage every so often...
For anyone wondering about power curves between LO5 & LT1:
I tried finding posts about this swap, but the search engine here seems to not like "LT1" as part of the query... It gives me a lot of completely unrelated posts.
Who here has done an LT1 swap?
What did you do for TC control?
Originally, I was going with a new GM ZZ4 shortblock, Vortec heads, and adding a 3rd Gen F-body TPI (Edelbrock vortec tpi intake)... all in the quest for a nice torque curve. (ZZ4 is now discontinued as well)
I Prefer to use readily available parts from the GM parts bin, whenever possible. GM had to engineer parts to last through at least their warranty period of 3-5 years... Aftermarket stuff is usually 90 days to a year or two at best. My experience is that much of the aftermarket stuff out there is reliable at being unreliable, fits...kinda-sorta-with help from a die grinder, and when the part fails, you are left stranded on the side of the road, hundreds of miles from home because no one has it in stock (special order), or ....its a long discontinued product that initially required you to fundamentally change the way GM designed it, so much so, that no stock parts can save you unless you can find everything last GM part you tossed into the trash heap.
Anyway, here's my reasoning.
#1.) TBI sucks... it does the job, but its pretty damn inefficient when compared to a properly-tuned Q-jet or direct injection systems... GM used it because it was very cheap to make... A hunk of machined cast aluminum, some vacuum ports, 2 injectors, a throttle A/F blade, and few sensors... really not complicated in any way.
#2.) The truck variant of the LO5 is doggy; 1992 LO5 C/K variant was rated at 210hp and 300ftlbs/tq. The TBI is what it is, swirl port heads just plain suck, and it lacks the roller valvetrain GM added to passenger car SBCs in 1987.
#3.) The LT1, was an amazing leap in performance. The '94-'95 B-Body LT1 was rated @ 260hp and 330 ftlbs/tq, plus the Caprice curb weight is very similar to a K1500 ext/shortbed. The B-Body LT1 iron heads flow exceptionally well & GM used them as the basis for the L31 Vortec design. The LT1 TPI plenum was a step up from the smaller '85-'92 TPI layout. Both develop healthy, broad, low-end torque curves, which is great for towing. Both engines were mated to the 4L60E (700R4E) so stock wiring can be retained and no fitment issues. Power steering will need to be looked at because the B-Body LT1 used a very undersized PS reservoir & pump for the car's size and weight, so it has failure issues when worked hard...
FYI:
The Optispark can be an expensive PITA... especially if you use aftermarket Opti's which have generic optical sensors. (Cant beat the original GM-Mitsubishi one)... the later design, "vented" Opti is pretty reliable, so long as you check the vent line for damage every so often...
For anyone wondering about power curves between LO5 & LT1:
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