As the title says, I just bought a 67 Firebird which is in decent shape and a good driver as is. I am planning on building the car inside out, back to front- planning on a 10 point cage allowing for full interior, currie 9" rear and a calvert racing leaf setup. So the big question is do I go with a big single on a BBC, or jump on the band wagon and go LS. Before everyone shouts LS, I would give the shortblock a full rebuild with full forged bottom end same as the BBC, so slapping a junkyard engine in the car and pulling a Richard Holdner is out. Building either engine will be pricey regardless. I have a local builder that will build me a very stout 4L80 with a manual VB and brake, who also swears it will hold up to my goals for the car. Which way to go?!? #ad

 

If I were starting from scratch, and had the funds, it would be a BBC with a really nice set of heads and a hydraulic roller if all I wanted was to go wicked fast.

If I wanted to be fast and still drive nice with better weight bias, it would be a LS3 with forged rods and pistons.

I would control either with a Holley EFI.

 

A proper big single turbo for a healthy BBC typically will be about double the money, so I see the BBC as a much more expensive build. I just replaced a BBC with an ls, and the size difference is drastic.

 

I would have to vote LS . They are smaller, lighter , cheaper to get to your goal. What is your goal? Nice car by the way. Street car? strip car? Corner carver?

 

Big single on a SBC .

 

The car is going to be used on the street no corner corner carving. Not my thing. I would like to keep it running on pump gas as well. I know the LS is an extremely capable platform, but a boosted big block just gets my heart rate up. I know the LS would probably do better on the street, but like I said, it i'm torn...

 

For me, if I were looking for 1200+ whp I'd look at the big block. Weight is the same as hp, so if you don't care that it's nose heavy, and just like the BBC, then that's the answer. Anything less than 1k whp, it's tough to beat the ls platform imo.

 

Honestly I want a car that will run into the 9s, and I want to run drag week someday. Not that I would count on being really competitive, just finish.

There is an all iron pontiac engine in it right now, so an aluminum head bbc should weigh about the same, and it's a pretty fun car. How much lighter is a LS with aluminum heads than BBC?

 

ls3=418 lbs
454 iron head=590
454 aluminum head=522

If your going to street drive it the LS gets my vote, you can make up the displacement with boost. Parts are cheap and plentiful, all the turbo stuff is available off the shelf in a million configurations, if (when...) something breaks replacement parts are easy to find. The weight plays a roll in all driving situations and 100+ pounds over the nose is going to be noticeable.

Or just blow the college fund, get an LS7, change the pistons and have the best of both worlds

 

A well balanced chassis is a good thing whether you like corners or not. The car will drive better in general and be easier to hook.

 

9s is so easy a caveman can do it. My junkyard 4.8 is WAY down in the 9s. It should be in the 8s next year after I smack it in the face with 30+psi.

 

Ok, so 100 lbs off the nose is pretty significant, and will help offset the added weight of the cage.

I like the idea of blowing the college fund, but I don't have to! Here is a little background- I just retired from the Army after 24 years of service, I am still on terminal leave until January 1st, and no need to burn the college fund as I signed my GI bill over to my son. I bought a 70 GTO when I was 14, and had it until I was 24. It wound up a 516" BBC, turbo 400, 4.10 gears- ran 11.10's on motor and 10.20's on nitrous. Trying to tote a car like that around in the Army, when I usually couldn't afford a house with a garage made me feel guilty. After numerous attempts from people trying to steal the car, I put it back on my parent's farm, and sold it a year later after sitting and having raccoons and cats crawl and poop all over it. Worst day ever... I told my wife I would have another car when I retired. I had been looking for a 67 Firebird specifically for quite some time, but same old story- too much money, rotted piece of junk, my brother has the title etc... So I gave up, and started looking for other platforms to use, but I stumbled on this one through Facebook marketplace, called the owner, and within 45 minutes I was on the road with trailer in tow and a pocket full of cash. 4 hours later I owned the car.

Anyways, common sense is telling me LS but childish giggles push me to BBC. I don't know much about LS engines, so I should probably get to learning!

 

I too vote ls.
It doesn't matter which LS. they will all make your goals. A decent camshaft, a s475 or s480, a 4l80 and a decent convertor.
Properly shopped and built you can meet your goals for less then a decent set of heads and valvetrain for the BBC.

 

Decide on an power goal and decided what RPM range you want it at.

BBC is defiantly more expensive, but the used aftermarket for them is huge, so you can shave off a ton of cost there. IMO you could make a BBC more street friendly. It will make like power at much less RPM and boost. Which will make the pump fuel goal more of a reality. You can also gear it extremely tall without as many downsides as a tall geared LS has as well.

That said if 9’s and street friendly are the main goals, you won’t beat the LS dollar for dollar. Might need race gas and or a healthy amount of meth injection to get there. The LS3 platform is far from common or cheap. Look into a simple 4.8/5.3. The alum 5.3 is the way I’d go personally. For example my tiny cam 4.8 is going 9 flat at 152ish on 20psi @ 3100lbs. Oem heads, ARP cheapie bolts, LS9 head gaskets, and a china s480 turbo. That was on a 3.25 gear and 30” tire... not much over 6k through the traps. Far from ideal for an all-out race setup, but very street friendly. Same combo on a 3500lb car would get you in the 9’s easy. 5.3 on the same setup has trapped 3-4 mph higher at like boost levels.

 

Wouldnt physical size also play a role for fabrication reasons ?

If you were gonna build a BBC from scratch , then budget isnt a deal breaker .

Is this going to be EFI ?

 

I'm not too familiar with the LS platform, but I am not foreign to engines. I tend to overbuild the bottom end (Harleys), and try to ensure they last as I am not easy on them at times. I have been thinking 5.3 or 6.0, but most of them are around 9.5:1 compression which seems to be quite a bit for a pump gas engine. My inital plan was a 496" BBC around 9:1 compression, good heads and a S488. John at LJMS seemed to think 6-8psi would get me to my HP goals with no issues.

Based on some calculators 900hp would get me comfortably into the mid 9's and 1200 or so would get me into the contenders bracket for street race power adder classes (cannot run over 8.50) at drag week.

Now onto LS questions- do I bother with a forged bottom end and good heads, or find a junkyard engine, pull it apart, open the ring gaps, stab in a cam and turbo and go for broke?

I am also wanting to go with fuel injection, but I have been leaning heavily towards throttle body EFI, namely Holley and FITECH. More or less because of the benefits of air/fuel going through the venturi adding to the cooling of inlet air temps in addition to an intercooler, also simplicity.

Please feel free to tell me I am all jacked up, I have been out of the go fast car scene for about 15 years or so.....

 

A good set of pistons and rods (rods for sure) isn't a bad idea when nearing 1k. The gen 4 rods are pretty stout, but not bulletproof. The rest of the short block is good. The small bore, and the chamber makes the Ls stuff very efficient, so 9.5 isn't a bad cr, but if looking for big boost on pump you could drop it some with a piston, or head change. I plan to run e85 all the time, or pump, and switch to race fuel at the track.

 

I was thinking a set of boostline rods and weisco pistons for sure. Also been looking at a set of blueprint heads as well. 258cc I take runners? That seems pretty huge for something at 364 cubic inches. It seems like nobody runs forged cranks. I'm guessing because of the super beefy main caps, and keeping things under 7k rpm. I'll m just not too sure about the ls accessory drive either. The car only has a water pump and alternator. That's it.

 

Trick flow heads are the brand you want for the LS, if you do go aftermarket. John is a guru on the LS platform and can put together the parts you need to achieve your goals.

 

Not everyone keeps them under 7k. There are lots of guys turning them 8k+ with stock bottom end.