What's new
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.

Opinions on my 454 TBI build plan

S

Seaark24v

Registered Member
Joined
Dec 30, 2009
Posts
19
Reaction score
0
Location
richmond, virginia
I'm swapping the 350 in my 91 suburban for a 90 454. Planning on keeping the TBI, and after reading as much as I can find, heres the plan:
Block is currently .040 over, 2 bolt with PP heads, Cylinders still have a good cross-hatch. Motor will be torn down, honed/bored as needed, flat top pistons. I am planning on 0 decking the block, using 100cc Vortec heads and cam selection is a vodoo 60200. This combo should give me a 9.4 static CR, and 8.2 dynamic, with .040 quench. Looking at full length headers, custom chip. I don't have dyno software, but hop to be in the 350/450 hp/torque area. Any input opionions appreciated.:bow:
 
Two pieces of advice. You need the 454 throttle body and injectors. Since GM decided they were needed even with the fairly anemic 454 vs. 350, I wouldn't question that.

I'd also plan on running a knock sensor (for 7.4) but will have to do some research on which one you would need. The Vortec heads won't tolerate a whole lot of timing compared to the earlier heads. With the 350 I ran into a LOT of pinging/knock retard from using the stock non-vortec timing tables. Running a knock sensor might allow you to get away with regular unleaded at that compression ratio.
 
I honestly made well over 350 and 450lbs of torque with a tiny (204/214) cam, pp heads, 7.8 to one compression, street warrior intake and headers. Should be easy with the improvements you are making. I am still on the fence on the vortec heads. They are really just a pp head made to look like a large oval. The flow is pretty meh. Since you are going to bore it anyway why not just get a pump piston and run the PP with some good valve work done?
 
Assuming the Vortec head design holds true on the BBC and SBC, the issue is more the Vortec chamber design than it is flow. I'm sure the BBC could use a far larger throttle body to make more power on the upper end, airflow is probably limited at the TBI as much as anywhere else.

Definitely other ways to get to the power goals. Running Vortecs is probably going to add to build cost quite a bit. But on a small block they are often worth 40+hp, not bad for just a head swap.
 
If you do some looking the BBC vortecs are nothing like the sbc heads. If they were I would have kept them. The 454 tbi is 650cfm which should be more then enough.
 
They are smaller and a little more heart shaped. They have a vane like a sbc tbi head and may run a little better but I still like the old pp heads. I went large ovals on my last build only because lpg takes more volume in the port.
 
From what iv seen the newer Vortec castings are a huge improvement in the higher RPM range, coming from increased flow. The peanut port heads that come factory make excellent torque considering the year and emissions. I have compared mine which is a Vortec with a oval port highrise carb intake with an adapter plate and a ported TBI, with all the fuel blah blah with it, full length headers, stock cam and roller rockers to a bored over mostly original TBI 91 454 but with headers and an Edlebrock intake and mine runs all over it from 0 till whenever, and i have bigger tires and over 2000 pounds more than him, but thats just a grain of salt. I would use the Vortec heads, buy an oval port carb intake, which youl probably have to port out to match the vortec gaskets like i did, port the TBI, and you should be happy with the output, I am. One thing though, most headers i have seen put the O2 down by the collector, i would recommend adding a heated one, so it goes into, and stays in closed loop much faster, its an easy upgrade and not very expensive, i used a 92 4.3L s-10 one and bought the matching pigtail from Advanced Auto. just my .02
 
Thanks for all the input. In my search for vortecs, I came across a set of 702 heads, 98cc. See the attached. Whats the scoop on these? Guy is asking $375, do you think they could clean-up without too much work?
 

Attachments

  • heads.bmp
    99.4 KB · Views: 6
  • heads2.bmp
    99.4 KB · Views: 4
Look at my Cadillac link above. Those chambers don't look like Vortecs.

From what I just found on Google, 702's are not Vortecs. If that is what you were told.

But pay attention to these guys, I know next to nothing of BBC's.
 
if going stock heads 049 or 781 is the 2 you realy want. large oval port and flow best for stock. just dump in bigger valves and good to go.
 
I just went down this road. I was not able to get a chip tuned properly. I had help from Eagle Mark, a borred out TBI, wideband o2, adjustable aeromotive FP regulator and all the programming stuff. My engine was 9.5 to 1, zero deck, older oval port heads and a roller cam made to work with a TBI. With a carb it made 415hp and 525tq. I have ordered a Holley HP 4bbl TBI system. I would recommend keeping the hp numbers down. Good new is I have all this stuff to sell. I just havent listed it yet. PM if your interested. I can email you a great BIN file to get you started.
 
You must log in or register to reply here.

Latest Posts

Top Bottom