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6K views 24 replies 7 participants last post by  N0DIH 
#1 ·
Hey everyone, I'm pretty new to this site but I am a huge Caddy enthusiast!
I just bought a triple black 1991 Brougham, it is in very good condition (very very minimal rust underneath) and is the smoothest riding car I have ever driven.
The only thing is (has the 5.0)its not really powerful as you all know. What should I drop in it? I want power but economy too!? I don't know too much about what would fit and so forth and also what about a tranny????

There is a 60,000mile '87 350 Iroc-z engine for sale locally, for $500.

Also I have found this:GM 700R4 automatic transmission about 65k miles on it was working when removed from buick roadmaster asking $200.00 obo

Do these sound good, or not even worth it?
Should I go with a crate engine? Transmission?

Any advice?
Thanks
 

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#3 ·
Congrats!

Might as well go with the TBI 350. Vortec heads can really open that motor up.

To get the TPI 350 from the Camaro would require some work, but would give you a good increase in power.
 
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#6 ·
This is a bit weird for me since I put an '87 Iroc 350 in my '91 Fleetwood a few years ago. Real easy swap, pretty much like taking your motor out and putting it back in. You CAN use your TBI manifold and fuel injection on that motor. Even the exhaust manifolds are the same. I had some problems with the fuel injection so I ended up using a carb on mine.
 
G
#8 ·
Great results. Mine had an aftermarket cam and I had dual exhaust with Magnaflows, it was a bit loud but it was pretty much even with my buddies 9C1 LT1 police car unitil about 65mph or so and then he would start pulling ahead. I dont have the car anymore but I will say that it guzzled gas very quickly.
 
#9 ·
Will this same swap work for a RWD 85 Fleetwood?

It's a 2dr so This is the type of power I'm looking for to move this fleetwood coupe and hop in front of unsuspecting rice rockets.:stirpot:

Did not know of the near seemless swap to a iroc 350 and 700r. THis is why I love this forum, learn something new everyday.
 
G
#10 ·
Swap was seamless only cause the '91 had a 305 Chevy. Same motor mounts/radiator/accessories all bolted up. The '85 has a 4100 so its gonna be a bit harder plus the '85 didn't have the 3:08 gears. I've swapped out V6's from G body cars and installed Chevy small blocks and I believe the 4100 swap would be similar. Here's a few pics of my old Caddy:









 
#11 ·
The TPI intake on a set of Vortec heads would likely shame a LT1 for midrange torque.

The LT1 will cream it over 4000 rpm, but below that would be one interesting race!

The SuperRam Intake would take both of them down...All other things being the same....
 
#13 ·
I am pretty sure Edelbrock has a TPI Base for Vortec heads. That is like a KILLER swap for an TPI engine. I have heard you can mod the stock intake to work, but some also say that it will never be right.

TPI's have bigger cams than LT1's (I think B/D AND F/Y). Still an old grind, getting a modern grind is STILL very beneficial.
LT1's and Vortec heads flow almost identical
TPI intakes make a lot more torque below 4000 rpm than the LT1 (you know, the main driving range, especially with a heavy car this is GOOD)
TPI engines are one piece rear seal and roller cam engines. So they are a very good foundation to start with. L98 heads aren't a bad start, but Vortec is lightyears ahead of the TPI/L98 heads.
 
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#14 ·
Vortec heads and a carb on an L98 would be pretty killer too. That was the next thing I was gonna do with my Caddy. A Vortec 350 thats found in countless GM trucks and vans is a great start and a cheap investment. They had just as much power as an LT1 but much simpler and cheaper to maintain. I wish I did a TPI or Vortec heads/intake/Fuel injection swap on mine. The carb worked fine but the gas mileage was terrible. My conversion van got with the Vortec 350 got much better mileage than my carbed L98 in the Fleetwood. You could buy a whole truck/van with a Vortec for less than $1500 or so and simply swap the drivetrain over and then sell the rest for parts and pretty much break even. IF I ever decide to modify another Fleetwood, I may go that route.
 
#15 ·
The carb and vortec heads is probably cheapest bang for the buck you can do. Just might be hard to pass emissions if you have to.

I used a Edelbrock Performer 1407 on my 455 Pontiac. Nice carb. But if I did it again, I would get a 1411.

For a 350 or smaller, get the 600 CFM, don't waste # on the 750, for street driving the 600 is nicer and snappier. You don't race the street car that often...

Just the Vortec EFI setup sucks, avoid! It can be done ok, but limited....
 
#18 ·
Vortec heads will improve power and mpg. And emissions too. They the best swap for a SB Chevy ever. Anything on heads is an improvement to the L05 heads....

You shouldn't have any problems bolting in a Truck Vortec 350. But you will need to either adapt the stock Vortec computer (and need it retuned by a tuner due to the gearing and shift points), or get a TBI intake and use the stock EFI. Toss in a F/Y Body cam and make an easy 290-300 hp or use the stock Vortec truck cam and make the stock 250-255 hp. Cam is almost the same specs as the LT1 B/D cam. The Vortec or B/D LT1 cam is a torquey cam so it will be a very nice driver and very good on emissions and mpg, probably better than the L05 cam.

Basically the heads are a nice design, flow well at low lift and good flow numbers up to 0.500 lift. Better than just about any other Gen 1 small block head from 1955 to the L05 (excluding the LT1 and LT4....which the LT1 iron head is what the Vortec head was patterned after, it is very close flow wise)
 
#22 ·
Oh but how COULD you deny yourself the power potential for such little work and cash! Nothing like a 14 sec D Body Cadillac!
 
#20 ·
Hey guys, this might be a dumb question, but are we talking a generation I or generation II vortec swap into a 91 Brougham? Basically, will a Gen. I be the same swap as a gen.II? Will either work in a 91. I really don't know much about these. But they sound pretty good.
 
#21 ·
To summarize:

Gen I Small Block: The venerable 1955-2002 design, varying in displacement from 262 CID to 400 CID with aftermarket blocks/cranks making it up to 454 CID. The last of the Small Blocks were dubbed "Vortec" for the trucks and were displacing 305 and 350 CID (L30 and L31 RPO Codes). These engines are NOT the L99 and LT1 engines.

Gen II Small Block: L99 and LT1 engines only. These were a variant of the Gen I SB, but incorporated a new improved cyl head port design that has a much improved flow, especially in the low lift range. The LT1/L99 incorporated a unique Reverse Cooling system based on the 1955-1959 Pontiac V8's with additional steam vent tubes. The L99/LT1 heads are NOT interchangable with any other engines. These engines have no conventional distributor and have a dry intake manifold (no coolant in the intake). This was the first sequential port electronic fuel injection Small Block (94-97 only, 92-93 engines were batch fuel injection like the L98 TPI's). It also included a first optical trigger ignition known as the OptiSpark and had a staggering 720x resolution on the camshaft (360 slots, measured on the leading and trailing edge), the crankshaft timing is based on that sensor also. The water pump is also driven off the camshaft so no belt is needed for safe engine operation.

Gen III Small Block: Starting in the early 90's GM realized that a new design was needed. Evaluations of a DOHC automatic Corvette (LT5) and a SUHC automatic Corvette (LT4) setup to have the same power by GM Powertrain and they had several GM Execs drive and evaluate what engine they liked best. Uniamous the LT4 powered Vette won. They were all shocked, none were allowed to see under the hood until the end of the test. GM started design of a new design, conventional underhood cam. This new design intially got released in the 1997 Corvette as RPO LS1. Most people incorrectly call ALL Gen III/IV V8's the LS1, this is incorrect, but most understand what is meant. The LS1 is an all aluminum 5.7L 345 CID engine with a plastic intake similar to the Northstar intake design. Displacements ranged from 4.8L (RPO LR4), 5.3L (RPO LM7), 5.7L (RPO LS1 and LS6) and 6.0L (RPO LQ4 and LQ9). The 4.8L and 5.3L share iron blocks, but have different cranks. The 5.3L can be bored to a 5.7L displacement. The 5.3L, 5.7L and 6.0L share cranks, but the 6.0L's are all iron blocks. The 5.7L are all aluminum, the 5.3L's are iron and aluminum. The 5.7L has never been in the truck line. The Gen III 4.8L/5.3L and 6.0L have never been in the car line. The Gen III V8's ranged from 1997 to 2004.

Gen IV Small Block: The Gen IV was a revised version of the Gen III. Much interchanges. I don't know too many of the details, but the displacements ranged from 4.8L (RPdO LY2)/5.3L (RPO LY5/LC9) and 6.0L (RPO LY6) iron block in the standard truck line, and 6.0L in the GTO and Corvette (RPO LS2), the 6.2L in the Premium trucks (Denali, Escalade, Trailblazer SS and SSR (RPO L92)), and the 7.0L (RPO LS7) in the Corvette Z06. This is not 100% correct, it is best that I know at the moment so feel free to add more detail if you can! :banghead:) The block has been windowed like the old Olds V8's (not THAT bad at least!) to improve bay to bay breathing. And the most significant improvement, the DOD or Active Fuel Management features in the lifter valley to shut down 4 of the 8 cyls to improve mpg. GM has seen upwards 10-20% improvment in mpg with this.

Well, that is best I can do for now. I have a good LS1/LS6 book that has much on the trucks too. But I am at a loss for more detailed info on the LS2/LS7. Note not ALL RPO codes listed, there are many.

More info: http://media.gm.com/us/gm/en/news/press_kits/07gmt900/GMT 900 Powertrain FINAL 9-15-05.htm
 
#24 ·
Doh! I talked about it in the Exec test.... But forgot where it SHOULD have been!

Yup, Correction:

GEN II Small Block: L99 (265 CID), LT1 (350 CID) and LT4 (HO 350 CID)

Also to note: Gen I Small Blocks all had 5.7" connecting rods, save 1, the 400 which had 5.565" rods.

Also to note: Gen II Small Block L99's had 5.94" connecting rods, the longest of any factory Gen II or Gen II Small Block. Basically the difference in 5.94 and 5.7 is 0.24", the difference in the stroke of a 5.7 and a 4.3 V8.... (wait you say! 3.48-3.00 is 0.48 not 0.24, but the difference is on both sides of the crank.... 0.24"x2=0.48, the difference in stroke to a 350 and 265....

Gen II Triva! The LT1 can be made in a 302 Gen II by using a L99 crank and rods in a 350 block with the 350 LT1 pistons.



http://en.wikipedia.org/wiki/Chevrolet_Small-Block_engine



I'll post the displacements later, I know them well (worked on a lot of them....) Anyone know?
 
#25 · (Edited)
More Gen I info
Gen I Small Block displacements (US) 262, 265, 267, 283, 302, 305, 307, 327, 350, 400. The 383 was a marry of the 400 crank in a 350. The 383 was GM made in the later years but never factory installed. The 350 was a long stroke 327, the 302 is a 327 block with a 283 crank, etc. In Australia they had some variation of the Gen I engines, but not sure how related.

Basically the displacements were generational:

265 was stroked into a 283, and was later replaced by a 327. The 327 got a 283 crank and became a 302. So they took the 327 crank and tossed it into a 283 and made a 307. More torque was needed and the 327 got stroked into a 350. The 305 was a destroked 350.

Oddballs..... But none the less, family....
The 262 shared nothing with any other Chevy small block. It had a slightly longer stroke than the 305 (which didn't exist yet) and tiny bores.
The 400 had larger siamesed bores, shorter rods and longer stroke not shared with any other small blocks.
But in all small blocks, some of the parts could be interchanged with others to make new combo's like a 272 CID engine (3.1" stroke in a 305 or a 265). Or a 311 CID V8 (350 bore, 262 stroke)....

The possibilities are almost endless....

Gen I Trivia: The V6's were based on V8 counterparts.
262 was a 350 with 2 cyls lopped off
229 was a 305 with 2 cyls lopped off
200 was a 267 with 2 cyls lopped off

The Gen I small block lives on in the 262 V6 which is still made today.... I think it is called the Gen Ie engine.
 
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