Guest Anonymous Posted January 24, 2001 Share Posted January 24, 2001 I was lucky and got my 71 240 with a 1987 5L Z28-700r4 already aboard. It looked like a well done Jags that Run conversion. The 305 had a TPI-roller cam set-up but lost its bottom end shortly after I got it. I was cash limited and got a 350 crate engine with a mild cam that should have yielded 300hp with the smog legal exhaust system. The engine has worked out well and I am ready to upgrade. Question 1. Any advantage to upgrading to a roller cam set-up. There are no bosses to mount the roller guides on the crate engine block. I have all the roller followers, guides etc from the 5L. Any good words on a good roller cam set up and what it would buy me performance wise.? Question 2. The TPI setup is working well but I have heard that the performance chips offered by Summit Racing etc work very well. Any body had any experience with them? Question 3. Since the car is a 71 can I get rid of all the smog pumps etc? What if anything would that do to the TPI system? Quote Link to comment Share on other sites More sharing options...
Owen Posted January 24, 2001 Share Posted January 24, 2001 Since I'm in so Cali too (Huntington Beach), I think I can answer #3. As long as the engine is the same year or newer than the chassis, you only need to conform to the smog laws of the chassis? But anything pre-73 is smog exempt, so my guess is none of that matters. Where in SD are you? Owen ------------------ http://www.homestead.com/s30z/index.html Quote Link to comment Share on other sites More sharing options...
Guest Fast Frog Posted January 24, 2001 Share Posted January 24, 2001 uncleEd: After posting my 1st response, I got to thinking-when you change out a cam, you change the engine dynamics regarding air/fuel needs. If your TPI sys is pre-programmed with a chip, you'd need to re-chip your sys. So, you'd need collaberate with an aftermarket chip maker as to what chip would be applicable for any given cam dynamics. As I mentioned, other members of this forum may have a wealth of info about this subject. Quote Link to comment Share on other sites More sharing options...
pparaska Posted January 24, 2001 Share Posted January 24, 2001 Roller Cams: The difference in the lobe shapes between a roller and flat tappet cam has much more to do with the kinematics of how a flat tappet and a roller operate on a cam than with what kind of linear valve lift ramps the cam is designed for. If a flat tappet and a roller cam were designed to have the same exact valve lift/duration curve, the lobe shapes (profiles) would be very different only because of the kinematics of how they work. But a roller cam can be designed to have more area under the lift/duration curve than a flat tappet, for the same valve spring requirements. That's where the broad power curve comes from. The roller cam, even a mild one will give a wider power band for the same valve spring requirements. Plus there is less friction, so less lost power, and they wear much better for aggressive grinds. Most of the aftermarket companies make roller lifters that can be fit into the old non-roller blocks. I hear that the Comp Cams retro hydaulic lifters are very heavy though. The solid ones are lighter. But I don't know if you can get and Extreme Energy mechanical roller setup, as it's not advertised. I'd bet you can't just put their regular hi-po solid roller lifters on an Extreme Energy hydraulic roller cam, but who knows - worth a call to the tech line. Personally, I prefer solid lifters. Quote Link to comment Share on other sites More sharing options...
Modern Motorsports Ltd Posted January 24, 2001 Share Posted January 24, 2001 others have used your same OEM roller setup on old non-roller blocks, takes a bit of work but nothing v. difficult. Seen as you have your rollers etc already it could certainly be worthwhile. Roller or non roller, either will run and can give you same power but NOT with the same manners or overall dyno curve. Roller is a fatter and flatter curve as a result of their faster ramps. I wouldn't rec'd solid lifters unless you have to go past the rpm's of hydraulic setup. Just extra maintenance and noise with no gain UNLESS you must have that extra power (like in excess of 450hp for ie. on a 350sbc). I only know one racer of many running solid's among roller setups FWIW. Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted January 25, 2001 Share Posted January 25, 2001 Is this a GM crate motor? If so I'd check again for the roller bosses, I thought ALL GM blocks after a certain date had the bosses for a roller setup. Also, the 305 TPI intake is supposed to be more restrictive than the 350s - increasing your engines desire for air and not allowing it to breathe will yield less gains than if it could breathe. I agree on the ECU chip stuff - is this car MAF or MAP? If MAP then you'll have to be careful althoug if it handled the 305 to 350 "upgrade" without changes I'm surprised! It's possible that further optimizing some of what you've got will yield gains without a cam swap - worth a shot no? Quote Link to comment Share on other sites More sharing options...
Guest Drewz Posted January 25, 2001 Share Posted January 25, 2001 The computer on the 305 has one of the leanest chips GM put out. Also the computer is an old model that does not lend itself to too much fine tuning. If you are not looking for a lot of horseys(350 and under) you can use the system you have with a 350 performance chip as the computer has the same pin setup as the same year 350. The injectors are smaller but get a guage and adjustable regulator and run the pressure 2 or 3 lbs. higher than stock. Hope this helps. ------------------ The only stupid question is one you wanted to ask but never did!!! Drewz Quote Link to comment Share on other sites More sharing options...
pparaska Posted January 25, 2001 Share Posted January 25, 2001 Ross, I know the solid lifters aren't needed for my purposes, I just like the sound and the solid connection. Pulling the valve covers every few 10K miles to adjust them will be fun, since it's easy to get at and the Pro Magnum rockers are so nice to work on. I adjusted them all last night in less than 20 minutes and it was SO EASY to get at and do. I only like one thing squishy and it doesn't have to do with a car Seriously, it's like the LS1 and Mustang II suspension discussions of late - I don't NEED solid lifters, I just WANT them. UncleEd, I'd look into whether that engine can run the OE rollers - rollers are definitely the way to a broad torque band. And there's nothing more fun on the street for day-to-day driving than a broad torque curve, IMO. ------------------ Pete Paraska - 73 540Z - Marathon Z Project pparaska@home.com Pete's V8 Datsun 240Z Pages Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted January 25, 2001 Share Posted January 25, 2001 Regarding your smog pump question, I'm running a '91 Camaro TBI 305 without air pump or cats and it runs great. The ecm doesn't know the difference. If you stick w/ the GM TPI setup and want to do ongoing mods you may want to consider learning to "burn" your own chips. The equipment to do this runs around $200. For more detailed info on this and other late model TPI stuff check out www.thirdgen.org ------------------ '71 240 '91 TBI 305,700R4 w/ shift kit Quote Link to comment Share on other sites More sharing options...
Guest Fast Frog Posted January 25, 2001 Share Posted January 25, 2001 uncleEd: I've got a 383 with an aftermarket TPI sys and Accel DFI engine mgmt setup. When I first installed the 383 6 yrs ago, I had a Crane 831 hyd cam which was great on low rpm but at 45-4800 rpms it started to die fairly fast. I later added a Paxton SC which cured some of that but getting to 5500 was still an effort. A yr later I installed a Crane hyd roller (621) retro fit cam kit and what a difference!!! I had almost as much power with just the hyd roller as I had with the old cam and the SC (I was only running 5-6lbs of boost with the Paxton)! Put a non-roller and a roller cam side by side and you can see the diff. The roller cam looks like the side of a boxcar!! Faster opening and higher lift for the same duration as a non-roller cam. Crane cams and I'm sure other popular cams merchants do have retro fit roller cam kits that fit non-roller blocks. My block once belonged to a 72 350 Vette. This should answer your 1st Q. I can't say too much about your TPI setup cause it operates by a ROM chip. Mine is programable with a laptop. But I think chips work pretty well-other members of this forum have much more experience with chips. Q3: I live in Colo and the state is not as rigid (except front range areas around Denver) about smog stuff. Eventho the fed clean air laws apply to all, many states are much more relaxed than Calif. My 383 is in a 76Z and I don't have a single smog device on it!! Welcome to HybridZ!! Rick Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted January 27, 2001 Share Posted January 27, 2001 I may be able to help with chiop software too as I've tried to collect what I've foound over the years.I'm not sure what all I've got but I'm quite sure I've got something that works for GNs at least. As for solid lifters - more power to you Pete but forget ever being able to run a knock sensor with whatever EFI setup you end up with. The noise from the lifters will retard your timing constantly.... That intake from the 305 still concerns me, I'd bet that if the motor isn't totally toast that you could get more power from the existing motor if you really tried. (shrug) Quote Link to comment Share on other sites More sharing options...
pparaska Posted January 27, 2001 Share Posted January 27, 2001 BLKMGK, damn good point on the solid lifters and knock sensors. My Eclipse retards the timing as soon as a hydraulic lifter starts making noise! PITA! Anyway, I'll be doing a head swap before I'd lay out the money to go to computerized EFI/ignition, as I have ALOT to gain from moving from even double hump heads. Quote Link to comment Share on other sites More sharing options...
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