96-99 7.4 performance mods

Performance modifications, tips & tricks

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HotRodV6
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Location: Conroe Tx 77304

96-99 7.4 performance mods

Post by HotRodV6 »

Ok, well I had a deal in the bag for an 02 8.1C3500HD but unfortunately it fell thru at the last minute. So ive been looking for other deals and came across a 98 7.4 454 vortec compete for a steal. Has 141K miles which isn't to bad and runs strong. I'm going to swap this and a 96' 80e with a 2500 converter into my Tahoe Limited. Also got a stock 7.4 harness and computer from a 99 3/4 ton suburban so the wiring should be plug and play hopefully.

My experience has always been small blocks with the exception of my first car that was a 455 olds. So I dont know a lot about BBC, but from what ive researched online these are pretty decent engines that can do well with intake/exhaust mods.

My plan is to install the engine with a set of hedman 1 3/4 primary 3" collector LT headersheaders and a full 3" dual exhaust with an x-pipe muffler. Cold air intake, underdrive pulleys, 07+ efans on my stock 34" radiator. And I want to do a cam swap, and was thinking either the 454HO crate engine can or the ZZ502 cam would be a good choice. Also gonna do the 0411 swap, and an HD2 shift kit in the trans.

Are there any other bolt on type mods that are worth wild or anything else I'm missing when it comes to these engines?

Thanks for any and all advice to a BBC newbie.

Whipped383
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Post by Whipped383 »

I'm sure can exhaust and intake will make you happy. Heads are a weak point tho from what I'm told

HotRodV6
Posts: 207
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Post by HotRodV6 »

Yeah ive read a lot of stuff online about these heads and it seems either people like them or hate them, but they are definetely better than the TBIâ„¢ heads of they replaced. And some say they are GM's best kept secret.

My plan for now o think is just basic bolt ons, intake and exhaust and tune and do the HO or 502 cam, I'm not sure yet and some 1.72 roller tip rockers and I think I'll be happy. Atleast for now. Lol

Whipped383
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Location: Salt Lake, 97K1500,ECSB, 383,Whipple,0411,Marine, 03K2500,CCSB,8.1&Allison, Whipple in progress

Post by Whipped383 »

Least you got options. Pickings are slim and spendy with an 8.1 very happy with where intake mods/porting and headers got me tho.

HotRodV6
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Post by HotRodV6 »

Yeah your intake mods turned out sweet! And I was super stoked to do the 8.1 swap.

But atleast the 8.1 heads are LS style and flow good from the start. I may look into some minor head and intake porting before doing the swap but not sure its worth the effort.

stroker97k1500
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Post by stroker97k1500 »

The cam and valve springs and stock injectors are the weak point in my opinion. I did a cam and springs, converted to a 0411 ECM and tuned it with a free flowing exhaust and drove it for about 2 years. Later put a Whipple on it and that woke up the motor. I blew it up (my fault not the motors fault) and then punched it out to a 460 ci, trick flow roller rockers, cam, Procomp aluminum heads, all forged internal rotating assembly, and the Whipple on it and it was a TON of fun.
I believe the BEST mod in my opinion is replace the injectors first with a better design(4 hole spray pattern drop in replacements on eBay ) or either factory LS1 injectors and retune the flow rate and then
Either put better aluminum heads on it or put a rear mounted turbo on it.

ORION OFF ROAD
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Location: *Salt Lake*

Post by ORION OFF ROAD »

stroker97k1500 wrote:put a Whipple on it and that woke up the motor.
I don't know a motor that doesn't "wake up" with boost lol. I've never heard "I boosted it, but didn't notice a difference" : )

In my own experience in building, and racing engines. There's no sense in bearing around the bush. You could spend $3k on engine mods, or just boost it and do nothing else. Boost always wins.

We tried this once on a round port big block. The round port heads are the worst flowing heads. And every single individual said "ditch those". We pulled an engine out of a '70s truck. Put a blower on it. And hit well under 10-seconds. Longevity wasn't great lol. But we did it. And from that point on, I learned that boost is the only real answer to the question "How do I get power" because it overcomes every other weakness. Heads don't flow worth crap? Turn up the boost. Small cam? Turn up the boost. Lol

HotRodV6
Posts: 207
Joined: Fri Jan 05, 2007 11:11 pm
Location: Conroe Tx 77304

Post by HotRodV6 »

stroker97k1500 wrote:The cam and valve springs and stock injectors are the weak point in my opinion. I did a cam and springs, converted to a 0411 ECM and tuned it with a free flowing exhaust and drove it for about 2 years. Later put a Whipple on it and that woke up the motor. I blew it up (my fault not the motors fault) and then punched it out to a 460 ci, trick flow roller rockers, cam, Procomp aluminum heads, all forged internal rotating assembly, and the Whipple on it and it was a TON of fun.
I believe the BEST mod in my opinion is replace the injectors first with a better design(4 hole spray pattern drop in replacements on eBay ) or either factory LS1 injectors and retune the flow rate and then
Either put better aluminum heads on it or put a rear mounted turbo on it.

What cam did you run in your setup?

I was also looking into the Mercury Marine 454/502 Magnum cam that is the same .483/.483 lift as the stock cam, but 224/224 dur@.050 vs i think 204/209 of the stock cam and its a 115 LSA vs 118 for the stocker. Will work with the stock rockers and springs with no issues and ive read some stuff that says it should be good for an easy 25-30 horse boost. I found a like new pull out cam on ebay for 100 bucks, but im thinking the 454HO cam that is 211/230 dur@.050 with .510/.540 lift on a 112 LSA will be a much more worthwild upgrade and the cam can be had for less than 200 which isnt bad, and ive read that it too can be ran with the stock springs and rockers. Im def gonna do the 0411 swap and get a good tune.

Whipped383
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Joined: Mon Mar 01, 2010 9:12 pm
Location: Salt Lake, 97K1500,ECSB, 383,Whipple,0411,Marine, 03K2500,CCSB,8.1&Allison, Whipple in progress

Post by Whipped383 »

Especially at higher elevation

ORION OFF ROAD
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Post by ORION OFF ROAD »

Whipped383 wrote:Especially at higher elevation
Later on
Here at our high elevation we had a stock steel crank, stock block, and stock round port heads on a 454. We did put some h beam rods, and pistons. And a blower cam. But the heads stayed stock. Other than we filled the water jackets with concrete. That dragster hit a 6.91 quarter mile at our adjusted elevation of 9,000'

that's why it always cracks me up when people port heads, or replace heads on boosted applications. Because I personally hit under 7-seconds with stock ports, on the worst flowing big-block heads Chevy ever made. I can say with certainty that if we had swapped $3,000 heads onto it, the ET wouldn't have been better than 6.91

stroker97k1500
Posts: 2702
Joined: Thu Apr 12, 2007 6:13 pm
Location: Macon Ga., 94Toyota truck with LSX stuff

Post by stroker97k1500 »

What cam did you run in your setup?

I was also looking into the Mercury Marine 454/502 Magnum cam that is the same .483/.483 lift as the stock cam, but 224/224 dur@.050 vs i think 204/209 of the stock cam and its a 115 LSA vs 118 for the stocker. Will work with the stock rockers and springs with no issues and ive read some stuff that says it should be good for an easy 25-30 horse boost. I found a like new pull out cam on ebay for 100 bucks, but im thinking the 454HO cam that is 211/230 dur@.050 with .510/.540 lift on a 112 LSA will be a much more worthwild upgrade and the cam can be had for less than 200 which isnt bad, and ive read that it too can be ran with the stock springs and rockers. Im def gonna do the 0411 swap and get a good tune.[/quote]

http://m.summitracing.com/parts/CCA-01- ... plication/
I believe the above cam is what I used along with

cca-1411-16 rocker arms(later swapped to better trick flow rocker arms than these)
cca-924-16 valve springs
cca-7815-16 push rods
cca-4779-8 need two sets, spring spacers, replaces the rotator cups
cca-4501-16 rocker studs

stroker97k1500
Posts: 2702
Joined: Thu Apr 12, 2007 6:13 pm
Location: Macon Ga., 94Toyota truck with LSX stuff

Post by stroker97k1500 »

http://s208.photobucket.com/user/stroke ... 6.mp4.html

I ran across this video I took just before selling the truck with the gen 6 based (460ci) bbc. It was a 0-105 ish mph run In 4hi
It would have been a lot quicker if it had smaller non mud tires (285-75-16) and it was a tiny 1.6L Lysholm/Whipple blower non intercooled. There was a bunch more potential there, it's just how much do you want to spend to get to (X) fast lol
A rear mounted turbo would amaze you on your stock setup.

This was some pictures of it

Image
Image
Image

HotRodV6
Posts: 207
Joined: Fri Jan 05, 2007 11:11 pm
Location: Conroe Tx 77304

Post by HotRodV6 »

Looks nice and always love the sound of the blower whine!!!

Its funny you mention a rear mount turbo, i had one in mine when doing the 8.1 swap, and have been thinking about doing it here as well. But will get it up and running NA first. Also been looking into doing the ZZ502 heads cam and 502 ram jet intake swap as well down the road, was gonna do the ram jet on the stock 7.4 but apparently it doesn't fit without some machine work, and for what one cost id rather put it on better heads than machine it for the stock heads.

stroker97k1500
Posts: 2702
Joined: Thu Apr 12, 2007 6:13 pm
Location: Macon Ga., 94Toyota truck with LSX stuff

Post by stroker97k1500 »

The crate 502 ramjet is a bass ass setup. I would have loved to have had that motor and forced induction would have been just badass on that setup.

HotRodV6
Posts: 207
Joined: Fri Jan 05, 2007 11:11 pm
Location: Conroe Tx 77304

Post by HotRodV6 »

stroker97k1500 wrote:What cam did you run in your setup?

I was also looking into the Mercury Marine 454/502 Magnum cam that is the same .483/.483 lift as the stock cam, but 224/224 dur@.050 vs i think 204/209 of the stock cam and its a 115 LSA vs 118 for the stocker. Will work with the stock rockers and springs with no issues and ive read some stuff that says it should be good for an easy 25-30 horse boost. I found a like new pull out cam on ebay for 100 bucks, but im thinking the 454HO cam that is 211/230 dur@.050 with .510/.540 lift on a 112 LSA will be a much more worthwild upgrade and the cam can be had for less than 200 which isnt bad, and ive read that it too can be ran with the stock springs and rockers. Im def gonna do the 0411 swap and get a good tune.
http://m.summitracing.com/parts/CCA-01- ... plication/
I believe the above cam is what I used along with

cca-1411-16 rocker arms(later swapped to better trick flow rocker arms than these)
cca-924-16 valve springs
cca-7815-16 push rods
cca-4779-8 need two sets, spring spacers, replaces the rotator cups
cca-4501-16 rocker studs[/quote]

The cam you ran is really close to the 454HO cam, and for the 100 bucks cheaper price im thinking this will be my choice, and looked up the above parts and the prices arent to bad. Did the stock valve keepers get reused or buy the matching comp ones to go with the comp springs and retainers? I was also already looking at those same roller tip rockers that i think will work fine for a budget build on the stock heads and id upgrade to better full rollers on better heads/bigger cam.

So now, with your build NA, with everything you had done before the 460 build, what kind of power would you estimate you were making or did you ever dyno this setup? Stock is 290/410 and im just trying to get an estimate of where i could potentially be. I will be running 1 3/4 headers with full 3" dual exhaust with an x-pipe muffler.

HotRodV6
Posts: 207
Joined: Fri Jan 05, 2007 11:11 pm
Location: Conroe Tx 77304

Post by HotRodV6 »

stroker97k1500 wrote:The crate 502 ramjet is a bass ass setup. I would have loved to have had that motor and forced induction would have been just badass on that setup.

Yeah it is a bad ass engine with a bad ass price tag, i think i can look around and put together the top end and do the stock short block as a 468 build and still have a nice setup. But that would be way down the road.

stroker97k1500
Posts: 2702
Joined: Thu Apr 12, 2007 6:13 pm
Location: Macon Ga., 94Toyota truck with LSX stuff

Post by stroker97k1500 »

The cam you ran is really close to the 454HO cam, and for the 100 bucks cheaper price im thinking this will be my choice, and looked up the above parts and the prices arent to bad. Did the stock valve keepers get reused or buy the matching comp ones to go with the comp springs and retainers? I was also already looking at those same roller tip rockers that i think will work fine for a budget build on the stock heads and id upgrade to better full rollers on better heads/bigger cam.

So now, with your build NA, with everything you had done before the 460 build, what kind of power would you estimate you were making or did you ever dyno this setup? Stock is 290/410 and im just trying to get an estimate of where i could potentially be. I will be running 1 3/4 headers with full 3" dual exhaust with an x-pipe muffler.[/quote]

I can give you my old set of rockers if you wanted them. I did not like their appearance at the fulcrum point after 2k miles of use and changed them. I did forget to mention that you will need the matching retainers and keepers for the springs as well. I believe I have pictures of them being too small for the new springs on here somewhere.
The torque was very nice and (to guess) after tuning on N/A on the 454 I'd say 500tq and bw 450-to maybe?500 ...IS ON THE HIGH SIDE MAX HP but torque was easily at or over 500ft #

HotRodV6
Posts: 207
Joined: Fri Jan 05, 2007 11:11 pm
Location: Conroe Tx 77304

Post by HotRodV6 »

stroker97k1500 wrote:The cam you ran is really close to the 454HO cam, and for the 100 bucks cheaper price im thinking this will be my choice, and looked up the above parts and the prices arent to bad. Did the stock valve keepers get reused or buy the matching comp ones to go with the comp springs and retainers? I was also already looking at those same roller tip rockers that i think will work fine for a budget build on the stock heads and id upgrade to better full rollers on better heads/bigger cam.

So now, with your build NA, with everything you had done before the 460 build, what kind of power would you estimate you were making or did you ever dyno this setup? Stock is 290/410 and im just trying to get an estimate of where i could potentially be. I will be running 1 3/4 headers with full 3" dual exhaust with an x-pipe muffler.
I can give you my old set of rockers if you wanted them. I did not like their appearance at the fulcrum point after 2k miles of use and changed them. I did forget to mention that you will need the matching retainers and keepers for the springs as well. I believe I have pictures of them being too small for the new springs on here somewhere.
The torque was very nice and (to guess) after tuning on N/A on the 454 I'd say 500tq and bw 450-to maybe?500 ...IS ON THE HIGH SIDE MAX HP but torque was easily at or over 500ft #[/quote]

Ok, yeah I'll take the rockers if you just want to get rid of them. Ive ran the comp magnum roller tip rockers on several SBC and a 4.3 and a 2.8 Chevy V6 and never had any issues, but maybe the BBC just dont like them. I also figured the new springs would need matching retainers and locks.

I like those power numbers, so I'm fairly confident my Tahoe should scoot down the rd very nicely with the 454/4L80e and some 3.73 gears. Maybe get better hwy mpg than the stock 350!!!

I'm not exactly sure how much my tahoe weights, but I'm guessing its in the 5-5500 range. Does anyone know what a 3/4 ton suburban weights?

HotRodV6
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Location: Conroe Tx 77304

Post by HotRodV6 »

Yeah if you just want to get rid of them, I'll take them. Ive ran them on several SBC and V6 engines with no issues.

Your power estimates sound nice and close to what I had in mind.

Should make my "lightweight" Tahoe scoot pretty well! :-)

stroker97k1500
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Joined: Thu Apr 12, 2007 6:13 pm
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Post by stroker97k1500 »

I don't know the exact weight off hand but inside the driver door jam should say how much your Tahoe weighs. I would think bw 5600-6k# for the 2500 Suburban.
I will try to look for those rockers this week
Tuning this particular motor even in stock form REALLY wakes it up a lot power and fuel economy wise The factory tune is just pathetic really as far as performance goes, but for safety on pulling heavy stuff it did just ok.
The original N/a 454 with cam, springs ect on my First camping trip with a load of firewood and all camping gear with 2 people in the truck and at that time I had 3.42:1 gears and driving north on I-75 from Macon Ga to TN state line up hill but highway only I got 18mpg on the first fill up just taking it easy. The previous 350 and then 383 with marine intake in same truck never did that well on fuel. They were usually in the 14/15 mpg range
The way I normally drive I got bw 14-15mpg
Now with my last truck (01 2500 silverado) it had an 6.0 lq4 and 12-13 highway and 10mpg every tank full when the Magnacharger MP112 was put on it and with the supercharger it still wasn't 1/2 the towing vehicle that the 454 was and it took way more effort to get low end torque to pull up hills with it on overdrive..... The 454 just basically idled and had all the torque you would ever need and off you went.

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