Hey
Well, my 1991 Firebird W/ 3.1 seems to have jumped time @ 190,000 miles. Now I have a reason to install my 1970 454 engine in it. I've read a few articles but was wondering if someone had a link to the complete swap info on this crossbreed. I'm hoping to use the original exhaust manifolds since headers are way more than I can justify . But it seems to be fairly straight forward. Will be keeping the Turbo 400 trans. They've been together since when my Father-in-Law bought this setup in Nov. 1969 in an SS 454 Monte Carlo.
Any help greatly appreciated. TIA

 

start with this while I look for the thread with the stock exhaust manifolds:
https://www.thirdgen.org/forums/engi...swap-info.html

also, the '70 heads won't take unleaded gas, and if you can't afford headers, then you can't afford new exhaust seats. You'll have to sell your heads and buy some '74-up heads. '74 was the last year for large oval ports in 'vettes, and the first year of peanut ports in everything else. Still, with peanut ports and a 224/230-110 cam, 445 hp at 4900 rpm is just a set of headers and an intake manifold away.

 

https://www.thirdgen.org/forums/engi...swap-info.html

theres some good info


just a FYI, I was fitting my power steering pump onto my bbc today and ran into some very obvious space issues, so do some research and see if someone has figured out what pump/brackets to use.

 

https://www.thirdgen.org/forums/engi...-454-swap.html shows the deal with exhaust manifolds, and specifies which were used.

 

Thanks for the info.Will have to do some reading fur sure. I guess the most important thing to consider is the front end suspension. I'll need new springs and would like to keep , if possible, the same ( or close to the same), the handling characteristics my car has now. Can y'all recommend a supplier for this ?? What about a link ( connector ) to straighten the frame. Also, I figure, will have to go to " Pull a Part" to find a Z 28 rear end. Lots to find out. But ,since it's so damn hot, I'll have a good amount of time to plan this project.
Again , thanks for the links

 

What's so special about a "Z28" rear end?

Other than the 9 bolt diff that was offered, all third gens got the same weak 10 bolt diff. The only difference was gear ratio, drum or disk brakes, open or posi and in 1990, it was upgraded from 26 to 28 spline.

The Z28 diff is no different that an RS etc diff.

 

First, the suspension: You will need much stiffer front springs, the stiffest stockers are found on GTAs with automatic and A/C. That's also where to look for your next set of sway bars.
Now, rear axle: None of the stock rear axles are very strong. The strongest choice of all was factory installed in '90-'92 with the base 305 and automatic.
You don't get posi that way, but I'll get back to that. What you do get is the 7.625" ring gear, 28-spline axles, and 2.73:1 ratio. The fact is, a 2.73:1 can survive more torque than a 3.42:1, and far far more than a 4.10:1.
As for a posi, there are conversion-style lockers on the market for around $350.
If you manage to grenade that, then you'll be swapping in a Ford 9" rear.
The rest of what you typed makes no sense, so I'll assume you mean subframe connectors. Plenty of good choices on the market. Get weld-ins, not bolt-ins.

 

Thanks. Wishin' I could take the 12 bolt out of my wrecked 1972 El Camino. 3:07 posi I built myself years ago.
Yes, sub frame connectors. I saw some a while back and was going to take the dimensions of the picture and make one at work. I thought the Z 28 would be a stronger rear end. Don't know much about this generation cars. Started out with a 1960 Chevy Impala w/ a 283 then upgraded to a 409. I'm used to "Heavy Metal"

"also, the '70 heads won't take unleaded gas, and if you can't afford headers, then you can't afford new exhaust seats. "

I've been running this motor on unleaded gas since 1981 when I built it. I used 8:00 Forged pistons and with the closed chambered heads reached a comp ratio of 9:25 instead of the stock 10:5. Over jetted my 800 CFM spread bore Holley and have no detonation.

With the pictures in those links, I'm sure with time and attention to detail I'll get this project done successfully. Just a matter of getting all the pieces in the right place. Appreciate the help

 

Please realize that I had to type in generalities, not having info on whether or not your personal specific heads had ever had hardened exhaust seats done. Thus I had to assume it had not. I just try to make people aware of what all they're likely to need to take into consideration.
best luck!

 

Yes, I knew about the valve seats, that's why I went with low compression and a 160 degree thermostat.. Usta have water injection w/ a shot of methanol for good measure.
I remember when Chevy first put the 265 in Bel Airs in '55 ( I was 10 ) But that was no match ( at that time ) for my neighbor's 392 Hemi in a Desoto.

 

Why can't you take the 12 bolt out? Or was it damaged in the wreck?