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-   -   Vortec 8.1l in a street car (https://www.offshoreonly.com/forums/trucks-trailers-transportation/366092-vortec-8-1l-street-car.html)

Natedawg 04-29-2020 10:55 PM

Vortec 8.1l in a street car
 
Please let me know if I'm in the right place for this question. Im hoping I am because you guys are the definitive word regarding performance on these engines. Some build guidance would really help me out! This is going into a 1971 Cutlass, 4100lb car, 4l80e trans. Spirited street car goal. Keeping the stock heads. It's the cam selection and rear gears that would really help me out. Raylars cams dont make much sense to me, they seem to be geared for trucks and they dont publish their specs. I'm not opposed to their selection but I cant get a straight answer out of them. I dont need a cam that can move a 6000lb truck and still pull 7500lbs but I definitely dont want to overdo it either. Any input would be greatly appreciated. -Nathan

resurrected 04-30-2020 06:46 AM

I don't know much specifically about the 8.1, but I would say that "Spirited" street car with an 800 lb engine could be a paradox.
My brother had one in a Yukon, tons of torque, which is excellent for street use. So if you want to burn off tires at every stop light, it would be perfect! Just watch out for the first corner
Upgrade the suspension, brakes and put some serious rubber under it and you could achieve your goal, oh yeah and add bigger brakes

Keith Atlanta 04-30-2020 07:55 AM

Im not good at crossing over water to road performance but I can tell you the Raylar 600 cam is almost identical to the 741 cam.

Would any of you OSO guys use the 741 cam in a car?

Then, there is the Raylar 209, thats a good bit hotter and I think would be a sick cam for a car since its recommended to be dry exhaust in a boat.

SB 04-30-2020 08:06 AM

You can get pretty much any Normal BBC hyd roller cam ground on a 8.1l core. The only real difference is the firing order. TheAPBA 8.1l cam was crane 741 lobes.

So there you go. Choose what duration you normally would (weight/gears/trans/torque converter/what rpm you want power and to shift at/ etc/etc) and go get it done.

Here is several of Crane’s offerings:
https://cranecams.com/all-vehicle-cl...00-8-1l-01-09/

Sydwayz 04-30-2020 10:09 AM

I wouldn't put a late model 8.1L Vortec in a car. Without going crazy, you are not going to make over 500HP. And you are jumping into all kinds of not-often-charted territory when it comes to electronics and gauges and such. I've had 3 different trucks with 8.1L, and I love the setup. But the electronics are a world of their own. On an 8.1L that came out of 2500 Suburban/Avalanche with the 4L85E transmission, they are electronically torque limited in 1st gear so as not to destroy that transmission. On a 8.1L/Allison take out, the electronics are completely different as the Allison is/was stronger. I do get that you can buy them on the cheap as take outs. But you are not going to "escape" cheap.

I understand the appeal of putting a BBC in a classic car. But, if I was going to put a BBC in a classic car, I'd absolutely go with a ZZ502 crate motor or the like...

https://paceperformance.com/images/M28615388

Sydwayz 04-30-2020 10:12 AM

...or go with an LSX which is easy to make 500HP and there a LOTS of vendors who have packages to swap those in.

If you want the car to be "sprited", you need to dump the iron off the front axle.

https://encrypted-tbn0.gstatic.com/i...DwYMwZaLK8lU&s


BUP 04-30-2020 10:37 AM

LSX I would go with or anything current LS or LSA

Anyways the 496 will not have parts down the road as some are NLA already. Trust me on this, I work on more marine 496 s than anyone in the industry so I have to keep updated with them because of this. That's basically my point here as well..

Also the power to CID ratio and the power to weight ratio is one of the worst and archaic especially compared to whats currently on the market for power in the LS world. Just saying

Natedawg 05-04-2020 10:05 PM

Thanks for the replies all, I've been scrambling to finish a paver patio ahead of the weather. "Spirited" is relative but I can have plenty of fun in a straight line and do my best with the suspension and brakes on the corners. I'm sure with headers, cam, a tune, and a few mods I can hit 400hp and 500ftlbs. I was actually surprised to find out how many parts were compatible(or really close) with previous big blocks. I was torn between an LS engine and a big block, the 8.1l seems to be the best of both worlds to me. Unfortunately the aftermarket really never caught on. I'll be going electric for the water pump and steering, so I will be losing those accessories. Since the electronics are all LS based, I'm covered on the gauges and such. Hey BUP, what parts are going NLA? Fabbing custom stuff is part of the fun for me, as long as I can keep this ticking until the next modern gm big block comes out I'll be good. I'd love to hear any tips for rebuilding from anyone.


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