I wan to put a new cam in my 86 305 TPI Iroc.
I have not touched the heads or cam yet but I
am going to do the cam this week. Will this cam work? I do have pullies, digital 6, nitrous, 3.73's, all the goodies in the tranny, plenum done, working on the throttle body, heads, injectors and base as well.
CAN I RUN THAT CAM?
Please advise ASAP?

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Jamie James
1986 Iroc-Z 305 TPI
1.90 60 ft 14.15@ 95.75
1.74 60 ft 12.84@107.75 on the bottle.
My IROC:
http://personal.nbnet.nb.ca/jjames/homepage.htm

 

I bought a Crane Compucam 2040 for my 305 TPI. Hated the peanut. No, I don't think it's too much, but if you don't port the lower and upper intake, that's the limit. It's supposed to work with the stock ECM, though I still recommend getting a custom prom. 2050 is starting to get big. I cannot tell you how that cam will work under nitrous, though. All I can tell you though is boost likes cams with 115 or more LSA. I'm sending back my 2040 for the 2050. Decided to not reinstall the 305 and wait for my 355 (383?), and get a hotter cam while I was at it. Make sure to change the head gaskets and pop in a double roller chain while you're at it, time it in stock. Upgrade any stock ignition components (except distributor)to performance spec. You may consider a MSD-6AL so you can run a wider plug gap under boost. Check the damper ring, if it's cracked, split, old, dinged from a hammer, replace it, no questions asked. The outer rings slip and the timing marks are no longer accurate. Only install a damper with the proper damper installation tool! You may want to change you water pump if it's old (for $15, why not?) WARNING...changing head gaskets in the car with stock exhaust manifolds flat-out sucks. This requires the use of cuss-words. Check the valve seals and be sure to change springs to match the cam!!!You may elect to do some mild porting on the heads as well, this helps with more cam, but is time consuming. You'd also need to hot-tank the heads afterwards. You may not want to do this yourself if you're inexperienced in this area. As far as the cam swap, I never did it in-car due to clearance, so cannot help you, just don't knick a cam bearing! Good luck

[This message has been edited by dhirocz (edited March 20, 2001).]

 

Thanks for the information. Do you have a suggestion for a roller timing chain and gear? I am running a Digital 6 MSD, dynomax headers, accel coil, taylor wires, ADS superchip and other mods.
I plan to redo the heads porting and polishing and adding new springs. I am unsure as well what to add for springs, any suggestions....size, type etc? What about damper?

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Jamie James
1986 Iroc-Z 305 TPI
1.90 60 ft 14.15@ 95.75
1.74 60 ft 12.84@107.75 on the bottle.
My IROC:
http://personal.nbnet.nb.ca/jjames/homepage.htm

 

I wouldn't worry about getting a 'true' roller timing chain. There are double row and double roller. They often get confused. The double roller can give you up to ten HP (real world, 5HP) due to the rollers in the chain...the double row doesn't have rollers, but is designed for less wear and friction. These give almost nothing, but the price difference is amazing...You can get a double row chain from certain Auto-parts stores. They cost around $20, while roller chains cost up to and over $100. They are usually special-order. So I recommend the double row. Stock chains suck. And gear drives, even the quiet ones, are too noisy...the knock sensor pick up the noise and retards the timing (bad...).

As far as springs go, a double spring should be OK. I'd use a Crane set. I bought mine for about $60 from Jeg's. I didn't bother getting the reatiners and locks because I was re-using my valves and heads (why buy what you already have?) Just make sure to have the heads hot-tanked after porting. I don't have the part number for the springs with me, it's at work, but call Jeg's, they should be able to tell you which springs you need. Get stock diameter. Make sure to replace the valve seals.

Before you start, look at the front of the motor and see if it look's realistic, as far as the cam swap. In the car? Keep in mind there's an A/C core (similar to your radiator, forget what it's called) in front of your radiator that can't be removed without moderate difficulty. This requires special tools and a drain of your refrigerant. As fas as a damper, if you don't see 4500 alot, and don't plan for over 250 HP, a stock damper is fine. Otherwise, invest in a fluidampr. Just don't invest meg-bucks into a race-type damper. Either way, you're safe replacing the stock one. You need 6 3/4" (internally balanced SBC).

If you opt to pull the motor, it's best because you can add a better oil pump and freshen it a bit before reinstalling it. I'd recommend the 350 swap since with your list of mods, that'll net ALOT more horsepower, just by sliding a 350 block under your 305 TPI. Everything will work, even the heads. The cranks and pistons differ (balance and bore)between a 305 and 350. Just make sure the pistons are for 58cc heads. 10.25 is probably the highest 'safe compression ratio you can run. This setup was what I was originally going to do. You'll probably pick up 40-50 HP easy by the addition of the 350. If not, de-glaze your cylinders and toss in some moly rings...ARP main, head and rod bolts aren't a bad idea if you beat up the motor alot. Just another recommendation. -dhirocz

[This message has been edited by dhirocz (edited March 21, 2001).]