I bought a 350 out of a 91 van. The engine is tbi, and I'm pretty sure it has swirl port head. I'm replacing the heads and cam before I put the motor in cause I don't want the cam and heads that came from a van. I plan on using stock l98 heads, and would like to get a cam that isn't stock put can be used with stock heads. I have a full exhaust (Dynomax catback, no cat(may add one), and hooker headers.), I'll be using the stock converter for now, and it will be converted to tpi. I was considering a lt1 cam, a comp cam. I dont' want anything to extreme right now cause I plan on turbocharging later this year. Any suggestions? Thanx.

Ray D.

 

Is the block setup for a roller cam?

 

I dont think truck blocks got the actual factory roller system until the Vortec blocks in 96.

If thats the case, you will want to look at something like the Xe262h. I am not sure, but i beleive they offer an EFI version. Its the same lobe profiles, just ground on a larger LSA, about 112° i think it is. If you get a flat tappet cam, you will need lifters as well. They offer a cam and lifter kit for all the cams they sell. Simply add a "CL" to the part number.

Plan on at least upgrading the valve springs. Nothing fancy is required. Just something that is better than those chicken wire stock springs. Something like the Comp 981 springs would even do the trick. Its about $50 or so for 16 of those springs. They fit the factory spring pocket but are a bit stronger than the chicken wire springs that the factory utilizes.

To add on ME Leighs question, does the block look like this:


Or is it complete with all this goofy hardware:


If it has all the stuff in the second picture, does it have this on the front of the block, the cam retainer plate?:


If yes to the second to pictures, then you need a factory roller cam. If the block doesnt even look like that, then you need a flat tappet cam.

 

Sorry I can't tell you much about the block right now. I can't actually look at it yet. Didn't all blocks after 87 have roller cams or was that in cars only?

 

Ok. I finally got my engine to my apartment building storage room. I got the intake manifold off and my engine looks like the first picture except it doesn't have those things extending out of it. I hope that helps you. If you answer. Thanx.

Ray D.

 

It doesnt have the tapped bosses that protrude from the center of the valley? Then it would be a hydraulic flat tappet block.

Depending on what you want to do and what your budget is, you COULD convert to a roller cam via a retro-fit roller kit. Except they aren't the cheapest. Neither is the cam.

If a budget is a big issue, then you can use a hydraulic flat tappet cam, as that is what the block orginally cam with.

 

Is a hydraulic flat tappet cam bad or not good for performance, and how much is a retro fit roller cam?

 

Flat tappets have been used for years!!! There is nothing wrong with them. Rollers are nice yes, but to do a retrofit on your non roller block you need $1000 just have the roller cam and setup.

Or you can pay $150 on a hyd cam/lifters.

 

Cool. Any suggestions on a hyd. flat tappet cam to use with l98 heads. O quick question about the heads. Which would be better l98 aluminum or iron? Thanx.

Ray D.

 

If you're planning on turbocharging the engine later this year are you building this engine for it now? Or are you gonna rebuild the engine when the time comes for the turbo? What part of cleveland are you in man? Alot of guys up there like to cruise. check out the midwest/plains section of www.3rdgen.org

 

I'm gonna build it for turbo later; probably during this winter when I won't be driving it. I just want to build a nice street l98 to replace my lo3. Imports in my area are getting faster, and I'm starting to see alot of those Neon Srt-4's. I know people here on the boards have made some repectable power with the 305, but that isn't the rout I wanna take. I live in the Cleveland Bedford Hts area.

 

I would take the L98 alum. versions over the iron ones.

What transmission are you planning to use?
If an auto, what stall are you planning on going with?
What's the desired compression ratio?
What are the rear gears out back?
What is the desired RPM range?

Those are some of the important facts needed before a suggestion can be made. Also, i would highly suggest doing some port work to the L98 heads. With a little massaging, they can really be made to flow. Also, machine work to allow for greater lift will most likely be needed. Another thing to consider is screw in studs and guideplates (they go hand in hand most of the time). The factory pull out studs sort of become less than stable once higher spring rates/pressures are encountered, as well as more lift.

On a side note, if you're going to build for turbo later, you've got a decision to make. You can spend money now, on parts that will run for only a short while, only to rebuild it later. Or, save up and just build it for a turbo from the start. That includes good forged pistons, good rods and bolts, a better crank. I would probably convert to a retro-fit roller setup if that were my engine.

 

700r4 (until i go turbo. Then I'm gonna convert to manual six spd )
3000 stall. unless thats to high
Want compression to stay around 9 not over 10.
the gears will most likely be 3.42 or close to that. need to find 4th gen rear
rpm range im not sure about. if you could help me out with that. that would great. Im just throwing this number out there, but is 2500- 6000 sound reasonable? Thanx

Ray D.

 

Hey Stekman. Is the roller cam really worth it? If it is then I'll consider the retro fit. And I decided to just build the engine for turbo now, instead of later. I did some adding and price estimating and doing it now would be cheaper then later.

 

I kind of figured that's what you would end up doing.

A retro roller cam is better than a flat tappet in pretty much every way, other than price. Their lifters use a roller bearing that, well, "rolls" on the cam lobe. Tis reduces friction and prevents the lifter face from digging into the cam lobe when more aggressive ramp rates are used (the rate at which the valve is opened and closed). Which is a concern with flat tappet cams. This more aggressive design allows the valve to open quicker and stay open (in the more 'useful' range) longer. That makes power. That same design allows for more lift for the given duration. If you look at Comp's website, look at the xtreme energy cams. Look at the roller series and the flat tappet series (hydraulic, for both). You will see that for the same overlap, the roller wil have more lift. More lift makes more power.

All in all, yes they do make more power. But whether or not it's worth the price, is up to the person who is considering it. If you convert to roller, you will pretty much need a new valve train. You will need better springs, in fact i would recommend taking the heads in and possibly having them machined for more lift (milling the guide bosses) as well as having the spring pockets enlarged so you can run the Comp 986 or 987 spring, which is the recommended spring for most of the XE roller cams.

If this is going to be a turbo, it would probably be in your best interest to call Comp and see if they could custom grind you a turbo cam. Let them know what you want and they will make a few suggestions.

 

Ive had a solid rollers in all my motors, except my very 1st one.

The cam is the highest point of restistance in a motor, when you have a flat tappet, from the lifter trying to ride up the lobe of the cam. So to me its worth it but.......

Now if I had a limited amount of money, which I do now that im married) I would invest in a nice set of AFRs WAY before I spent my money on a retro-fit roller.....And Im sure almost everyone will agree with me.

Heads are what make or break the power potential of your motor, the heart of the engine. The cam controls where the powerband is, the brains.

Get good heads first!!!!

 

Im basing my suggestions off a retro fit hydraulic roller, not solid. It's up to him really if he wants to use a solid roller or hydraulic.

I would suggest heads first, like you say, but he's starting fresh, from the beginning. He's not upgrading. And for a turbo setup, i don't see him running stock L98 heads, just doesn't make sense. So either way, he has to get heads (or work the ones he has) and get a cam. And he's already said he's going to just build the turbo engine up front, so why buy a flat tappet cam, run it for a short time, then swap?

I say save for a roller setup and whatever you plan on doing for heads. (What ARE your plans for cylinder heads?)

 

Sorry I haven't replied in a while. For some reason my computer couldn't locate the server, but sbc fixed so whatever. For heads I was going to go with ported L98. 83crossfire told me awhile ago on the forced induction forum that port L98 would flow fine for a turbo engine, but I'm going to ask him and Guido again about that. When I call comp I'll ask there opinion and suggestions about roller or tappet.

Ray D.

 

i have fully ported and polished 113 heads. They flow great. They had 18 hours of porting and polishing, bigger valves machined in, manley stainless race valves, 30 degree backcut and a 3 angle valve job. They put my buddys 355 hsr iroc into the mid 12's and I hope to do the same with them in my GTA once I get to the track. They are good heads with the right work.

You aren't too far from me man. I'm in streetsboro, right down 480 from you. My dad actually works up in bedford at Ben Venue Labs.