TPI tips

[ryangreen19]

Hi all,
I am doing a TPI conversion on my '68 cst-10 327 this summer, I have already picked up the intake, 1227730 computer, small cap distributor and harness, although I think I am going to get a new one from EFI connection. The system is speed density as well. I am amazed at all the info I have found on the forums so far but I have a couple of questions still.
1) Has anyone used their in-cab fuel tank with a new sending unit instead of mounting an underbed tank ? I also understand I don't have baffles in my tank but thought I could add some foam to counter this similar to fuel cells.
2) The throttle rod has to go. I have read about and located the parts to convert to the 71-72 pedal style. Are there any alternatives to this ? I have read about the Lokar option but as I understand it I would still need to convert to the later cable style?
3) Camshaft suggestions. I have gathered anything less than 112 degrees LSA isn't advisable to get enough vacuum. I am looking for something would help make high 2's HP and close to 300 Ft-lbs. I am not going to be pulling anything or drag racing so a mid-range powerband is probably the best.

Thanks in advance

Ryan

[Ackattack]

I had a TPI 350 in my 72 GMC. I used the stock in cab gas tank with the stock sending unit (the '72 sending unit has a "return" line fitting on it. When I got low on gas, going around a turn, sometimes it would start to cut out, so just keep it filled up past 1/4 tank and you won't have any problems. I had a fuel pump mounted on the frame rail.

Honestly though, I was very disappointed in the TPI setup. Mine seemed to be running perfectly fine (MAF setup btw) but I felt it never had the low end torque like I was expecting.

When it came time to do a truck project like I really wanted, I ended up selling my 72 GMC. The fact that it was a LWB and I wanted a SWB and I was going to swap to an LSx engine made my decision to just sell it rather than do all the conversion.

So, if you can swing it, I'd look at an LSx engine rather than going to the effort of putting on the TPI system.

[mrhino]

I bilt a 305 tpi a few years ago, although it was for a Iroc the same theory applys IF you want to make good power and lots of torque, out of a TPI setup the trick is in the camshaft. if you do anything keep your cam choice small no more than 205-210 duration. I used a GM performance Ram jet cam, Made great power, loads of torque and with a 700r4. I got 25mpg on the hwy of coarse.

In truck I just finished I put in a 5.3l I also had to switch to a cable operated throttle. its no big deal, I found a member selling one, bolted it up and then used a lokar cable, its pretty easy. I did not use the in cab tank, however I think you would have to always keep 1/4 tank or more of fuel in it to keep it from losing pressure.

[Katrina/10]

Originally Posted by ryangreen19

Hi all,
I am doing a TPI conversion on my '68 cst-10 327 this summer, I have already picked up the intake, 1227730 computer, small cap distributor and harness, although I think I am going to get a new one from EFI connection. The system is speed density as well. I am amazed at all the info I have found on the forums so far but I have a couple of questions still.
1) Has anyone used their in-cab fuel tank with a new sending unit instead of mounting an underbed tank ? I also understand I don't have baffles in my tank but thought I could add some foam to counter this similar to fuel cells.
2) The throttle rod has to go. I have read about and located the parts to convert to the 71-72 pedal style. Are there any alternatives to this ? I have read about the Lokar option but as I understand it I would still need to convert to the later cable style?
3) Camshaft suggestions. I have gathered anything less than 112 degrees LSA isn't advisable to get enough vacuum. I am looking for something would help make high 2's HP and close to 300 Ft-lbs. I am not going to be pulling anything or drag racing so a mid-range powerband is probably the best.

Thanks in advance

Ryan

A 71/72 tank has a 5/16 vapor return port in the top right corner. Works great for an EFI return connection. The sending unit does not have to be changed. I used an external E2000 fuel pump on the frame below the tank.

A71/72 gas pedal can be easily adapted to the earlier firewall, and use a cable off TPI camaro to connect to the throttle body.

You will need to download a bin file to your 7730 ecm to eliminate VATS or your truck will not run.