couple of question is there any reason why i couldnt drop in hydraulic flat tappet lifters and cam in the block out of my 92 305, also i heard you cant reuse flat tappet lifters if they aren't with the original cam they were broke in with , is this true?

 

You can indeed run flat tappet lifters and cam in your roller block - but why? That's a DOWNGRADE...?

That's right, if you're reusing a flat tappet cam, you need to match up the lifters with each lobe (ie, lifter from #4 intake must stay with #4 intake)... Or else throw them out and get all new lifters. Remember, flat tappet cams wear out, so unless it's a very new-ish cam, I wouldn't even bother reusing it anyway.
Actually, i'd just be buying a roller cam, and reusing my roller lifters...

 

thakns for the info , and yeah the cams brand new, the only reason i was asking is because of the cost of roller cams, much cheaper to buy the lifters and put the cam that i have in.

 

oh, if you've already got the flat tappet cam, free, then I guess. But i'd still really reconsider, a roller cam is SO much better.
Besides, is this flat tappet cam the best one for your application anyway? You might be able to sell it to someone, then bite the bullet and buy a roller cam.

 

well this is more of a, budget oriented lets see what kind of numbers this makes project. but the set up is basically the 305 short block out of my 92 with lt1 heads gmpp lt1/lt4 carb intake the cam with something along the lines of 488 lift and probably a holley 650 on top and maybe a 50 shot

 

You will also need different pushrods, because roller lifters use shorter pushrods than flat tappet lifters.

 

Bad cam choice. That's the "RPM" cam, or the one you can get from Summit that's exactly the same, or the Summit one that has that same intake lobe on both intake and exhaust. That cam ESPECIALLY sucks in a 305.

For a REALLY GOOD budget build, leave your lifters and push rods alone; and snag you a ZZ4 takeout off eBay. They go for about $125 - 135. That'll cost you less than one of those "budget" cams by the time you get it installed, and run AHELLUVALOT better, and use less gas besides.

After all, the "budget" of the build might seem important right now; but when you figure out that you've shot yourself in the foot because the extra gas it's going to use without producing any more power is going, within just a couple of weeks, to completely wipe out any "savings" you thought you were going to "save" by using the el cheeeepo parts, it doesn't look so "budget" any more.

 

"roller lifters use shorter pushrods than flat tappet lifters." that was gonna be my next question.. out of curiousity is there any way to check my roller lifters to see if any are bad, i only ask because last year at the track i bent all the pushrods and broke 2 valves, apparently to much juice.

thanks chris

 

[QUOTE=sofakingdom;3182879]Bad cam choice. QUOTE]

well give me some numbers... what do you think i will make with that cam, and what could i expect with the zz4

thanks chris

 

Well, the ZZ4 makes 345 HP... you do the math

 

sofakingdom beat me to it. I was going to say ".488 lift eh? shudder".

The two cams might make similar HP at 5500RPM for example, but the ZZ4 cam would have a hell of a lot more torque, driveability and mileage. A better torque curve will get you down the 1/4 mile faster in the end.

Rebuild the lifters. If the spring in them is seized/destroyed/broken, you've found your cause. You can nab 3.1L V6 lifters, IIRC, to replace any bad ones you have. Factory replacement pushrods are cheap.

 

well just a follow up..... i'm gonna take your guys advice and go with the zz4 cam, im pretty excited to see how this turns out thanks for the input,


chris

 

For some reason, I think that's a good choice.

I don't think you'll be disappointed. My little bro and I put one of those into the L69 in his 87 MC SS. It was pretty impressive actually.

Might be a good idea to update the valve springs, while you're at it. Valve float, directly traceable to weak springs, is usually the reason for valve train parts breakage. Comp 981, Crane 99846, the equivalent from Lunati, Isky, Crower, etc. would be a good choice. Basically any of the top-line cam mfrs' 1.25" spring. I'd avoid K-Motion and GM, and any "stock replacement"; this includes the "Z-28" springs you can get for so cheap.

 

odered the springs last night, they were comp cams 982's... they should get here right around the time the heads get done at the machine shop. so once i find a carb i should have all the parts i need to get this project rollin, and again i have to say, appreciate all the advice and info

 

I'm running the ZZ4 cam with the "Z28/LT1" springs (actually been running the springs since 2001, with the Crane 2050 cam I had in the 305 before putting in the ZZ3 shortblock). I've run it to 6300 RPMs many, many times with no problems.

 

instead of posting a new thread figured id bring this one back, i got the engine running a couple of days ago, and man am i excited for a test drive, and wanted to thank you guys for all the input about the cam, now i come to you with another question i was wondering what gears you think would go good witht the setup, i originally thought 4.11's now im thinkin maybe 3.73's. i have less than a month before the first track opens and i want to get this last stuff straightened out asap. any thoughts on this would be appreciated

 

What cam did you end up with?

How does the motor run? Have you had it on the chassis dyno yet to see what RPMs it makes power at? That's the best way to pick gears.... find out where the motor makes the most power, and pick your gears to keep it in that range.

 

i ended up going with the zz4 cam... no hasnt been to a dyno yet, i still have some little things to do before i can actually drive it.....however it idles pretty good and has a hell of a lope goin ,i still need to add some timing and adjust the carb, but i think this is gonna be a screamer cant wait to get it to the track

 

heres a quick clip or its idle, since i was bored i figured i'd post it

http://s158.photobucket.com/albums/t...Video-0045.flv