Did some searching but didn't exactly find what I was looking or here it goes. This motor is for 86 Iroc enduro circle track car. The car originally came with an TBI 305 (187 swirls), WC T-5 and 3.08 locked rear. This oem roller motor has the peanut cam. However, the bottom end was wasted. For parts we have a TPI 305 (081) out of an 87 GTA AT car. Block is cracked so combining the two. Both are factory roller blocks. Being done this way because of the nature of this type of racing.

There are a few rules that must be followed. Using a q-jet on older oem aluminum intake, so must use a mechanical fuel pump. We are also using an HEI distributor. So the chosen cam must have the fuel pump eccentric/lobe. Tech can also be PITA's if non-stock/oem parts are used. Trying to go with a factory camshaft.

We are using the 86 Iroc's TBI 305 block with the complete 87 TPI 305 GTA's lower end. Which is presently assembled. The 081 heads from the GTA. The cam from the 87 TPI 305 is junk , so the cam choice was to be made, like this past weekend.

Originally was looking at LT1 takeouts but apparently they don't have provisions for a mechanical fuel pump. We were trying to stay around .450-.480 max lift with the present stock springs setup and guides bosses. Any suggestions on what would be an improving oem/stock bolt in? Obviously nothing from a truck or B-body. Do the L98 cams have mechanical fuel pump provisions or would we forced to look into something out of a zz4 ? Maybe there is something else I'm overlooking? Trying to avoid aftermarket because of "rule interpretations", especially during a teardown.

Moreover, will HEI's drive gear have to be replaced, with a gear for use with a roller cam? Is the fuel pump rod just your average sbc rod or is it something brass coated or the likes? TIA

 

The ZZ4 cam has a fuel pump lobe. For that matter, so does the L98 cam.

The ZZ4 cam runs AWESOME in a carbed 305. I highly recommend it. One piece of advice, though: DON'T try to use used stock valve springs. Since it has over .500" lift on the exhaust side, be very meticulous about setting the springs up, so that you get both enough seat pressure, and enough installed height to avoid coil bind.

 

If you could get past using the mechanical fuel pump,

The LT1 cam is .450/.460 lift.

I am currently putting this cam in my '89 LB9.

Ill let you know how the outcome is.

Sheldon

 

I have a L98 cam out of a 92 Z28. If you are interested pm me.

Oh yeah, You will be fine with a stock GM cam with the stock HEI gear.

 

Thanks for all the input guys. This car will be racing in circles, against other POS. So kind of limited by all the rules of various tracks. Going with the L98 cam since it now has a fuel cell and a mechanical pump required. I'm sure a backup motor will be slapped together, so a ZZ4 cam will get used next time. Well if the caged unibody and the rebuilt T-5 hold up for a while.

Wayne, I'm sure by now you have talked to Danny and thanks a bunch.

John

 

No problem, glad to help!

Hope the motor turns out strong and gives you good luck at the track.

 

'86 didn't have TBI, and '86 didn't have roller lifters.

You either have your facts crossed, or don't have an '86 engine.

 

Thanks for pointing that out. The year may have been incorrectly given to me. First was told it was an IROC, then also told a Z-28. Bought from the original owner with 77k original miles. Knows the owner personally. I thought it was more likely an 88 because of the 14093627 block, t-5, open 3.08 rear, tbi and 187 heads. However, I was also told the 8th vin digit was an 8 and not an E. The car is in NY, I'm in PA. I'll get the whole vin anyway or copy of the title, to see exactly what was cut up and gutted.

*** edit: well five7kid is correct. Buddy somehow read that 9 upside down and that 8 in the vin is actually an E. It was 89 L03 out of Van Nuys. Thanks.

 

Well what do you know, not all L98 cams possess a mechanical fuel pump lobe. There's a small symetrical cylinder type lump there, but the 10111773 cam, definitely doesn't have an actual lobe. Wayne, I pm'd you. Looks like we're back to square one.

 

Yeah, I pm'd you back and also talked to Danny. Guys I was so sure that it had the lobe, that I didnt check it when I shipped it. I was in a hurry to get it shipped out because you guys need it quickly.

I appoligized to Danny and offered to make it up to him. He said he was still going to use it. I hope you guys arent to mad at me. It was a honest mistake and wasnt on intential.

 

Right... that's the thing that works the mech fuel pump.

It's not a lobe. It's called an "eccentric". It's circular, rather than egg-shaped; and ground off-center with respect to the cam axis.

Go compare it to any other SBC cam.

Many other brands of engines use an actual cylindrical object made of stamped sheet metal that bolts onto the front of the cam, between the cam gear and its bolts.

So, your L98 cam, like everybody else's L98 cam, will work a mech fuel pump just fine.

 

Seriously now, thanks for the help. However, I've been at this for a long time and know the difference. Like the term "eccentric" was used in my 1st post of this thread. The ...773 cam doesn't have one. Only thing present, is very small and circular, but not egg shaped or offset. At this point, it's just easier to run a flat tappet setup. All L98 cams aren't applicable with a mechanical fuel pump, despite what's been written elsewhere. I'm pretty sure this is NOT the one & only 773, L98 cam without mechanical fuel pump provisions.

Nah Wayne, what can you do. Stuff happens. Thanks for getting it out asap. I talked to him briefly earlier. Definitely can't use it. He's gonna get back to me in a little bit.

Since one's available, looks like a 300hp/350 crate cam (24502476) is going in.

 

Might I recommend trying the LT4 HOT cam over the zz4 or lt1 cams in a 305. Im running it in my carbed 305 and it has a decent power range. If I get this thing to a track Ill let you know how it does.

 

Couple of more odds and ends to take care of before this Saturday. When gutted, jeez are these light. Pics were taken with a cell phone on 2/2807.

 

Well the cobbled together 305 powered the Camaro to a 3rd place finish. Without being able to properly stagger the tires. Then momentarily lost oil pressure going up the off ramp. Should've cut the crank, oh well. Have enough time between races to possibly rebuild or just use a 350. Maybe a rear swap too. Escaped with hardly any body damage. It did better than expected. Thanks to those that helped on this thread and the carb thread.