Hey guys, I am currently in the process of building another turbo car using my PT70 , out of the box Victor Jr. heads, GT40 lower/Down's box upper. This is on a stock block 302. Tremec TKO for a transmission. I read in a couple of searches that the stock cobra cams aren't necessarily desirable on a turbo setup. I was going to just run a stock GT cam, but I don't have one and neither does any of my buddies. I figure that we have all probably just thrown them away over time. I do however have a stock 1993 cobra cam with only 30,000 miles on it, so I was considering using it. Any specific reason to go with a stock GT cam over the Cobra???
Mike

 

cam specs

Cobra cam looks ok to me. How much power are you looking to make? What ratio lifters, RPM, compression, boost?

Do any of your buddies have an F-cam laying around? That would work well...

 

Thanks for posting that chart, I was looking for something like that earlier. I made 526rwhp 617 rwtq with my old carb/blowthrough setup on 14 psi, and would like to duplicate that with the new combo. I switched heads from Canfields to these Victor Jr.s as the Canfields had huge ports (ported to a 235cc intake runner) and I never really thought that I was utilizing all that airflow, also made it really sluggish down low until boost came on. I currently have 1.6's but have a friend who wants to swap for his 1.7's so that was the plan. I don't have an F303, but I am building this car to have a nice, daily driveable street car with a/c, p/s and all the amenities, so I'm not really interested in putting in a large cam. I had a Z303 in the blowthrough car, but this one is going to be stock computer, Pro M univer, 42lb injectors, and I don't want to have the stock computer dealing with anything that might cause an irratic idle, etc. I am looking to run around 15-16psi max, and with the stock shortblock I am looking to make peak power no higher than 5300-5500 rpm. The compression is right around 8.25:1 with the 70cc chambers on the victor jr.'s and my flycut pistons.

 

Sounds like the cobra cam will get you were you want to go. With those heads, I doubt you will require that much boost to make ~525RWHP.

It won't be the most efficient way to do it; however, if you don't want to spend $300 for a custom cam and don't mind running an extra 1-2 PSI to make up for it then I would say you are going to be just fine. The 1.7 rockers will help.

Have fun!

 

Thanks for the information. I talked to another friend of mine today and he says that he has a stock shortblock with around 50K miles on it with a stock cam in it, so I will now have a stock GT cam and the Cobra cam to choose from. I hate cam swaps, but I may try one out first and then switch out after awhile and try the other. Although I don't know that it would be worth the effort of doing so. If given the choice between the two, which one would you go with? I know that there are alot of people making good power with the stocker, so it makes it a hard decision, you just don't see as many Cobras that are turbo'd and it's also hard to compare if you're talking stock motors on the two as the Cobra has the advantage of the better heads and intake as well. Decisions, decisions...

 

Either will allow plenty of power to split your block.

There is alot of variation in the stock cams' duration at 0.050'' even if they have the same total duration.

You will need to map out each cam to determine which would be better. But the deference will likely be minamal.

The stock gt cam w/ 1.7 rockers seems to be a nice turbo setup if you wish to try that out.

 

Thanks again for all the advise, I think I may end up running the stock GT cam since that was my initial thought. If I had some extra cash right now, I'd opt for a small custom grind, but that will have to come later. I'll also be building an extra shortblock just for a backup, so I may go to a small custom in that one so it will be ready to run.