I'm in the middle of rebuilding the 305 TPI in my '90 formula. The plan for this car is to make it a good, dependable daily driver but have a little more performance than stock. I'm not looking to make it a monster, and im trying to get off fairly cheap, so a 350 swap is out of the question.

So far the plan is:
Port and polish the heads and intake
Adjustable fuel pressure regulator
New cam: cam will be a flat tappet hydraulic, as one of the roller lifters broke while getting it out of the block . I dont want to spend $250 for new lifters when i can get cam and lifters for less than that.

My questions are:
1.Will this cam work without mods to the stock computer (MAP system)
http://www.compcams.com/Technical/Se...umber=12-249-4

2. With these mods, will i need to step up a size when i buy new injectors?

3. Can i use the stock pushrods or will i need new ones for the difference in lifters. I dont have a flat tappet to compare with, but it looks like the roller lifters are longer.

Thanks for any advice you guys can give
Jon

 

1) yes, that cam should work with your stock map ecm.
2) no, with the adjustable reg you should be Ok
3) no, but iam not sure with that one. i think your right about the roller lifter being longer than the flat tappet lifter. i would look into some 1.6 RR or the 1.6 stamped rockers, unless you dont want to spend the money.

 

You know that you can't just slap a flat tappet cam into your roller block, right?

If you're starting with a different block then why not start with a 350?

Why don't you replace the one bad lifter? Roller lifters last a long time and I have replaced the cam and re-used the roller lifters...

???

 

that cam is made to fit in a roller block. but i do agree with you about the lifters. why dont you just try to replace the one that broke?

 

Thanks for the replys

Everywhere I checked they only sold the lifters in a set.

I dont have a lot of experience with roller cams, what would the difference be that i couldnt use a non roller setup in my engine? I thought all cams were the same specs. ( length, bearing location/size, etc.)

Also, if i can replace just that one lifter could i use a LT1 cam with the stock computer? I have a friend that has one that i could get for free if it will work.

 

the only major diff between the two cams are friction loss, but a TPI motor wont spin fast enough see the real potential of the roller cam. so in short the'll be little to no diff in power out put. iam not to sure about the LT1 cam. i know that its not too much bigger than the L98 cam. the Map system really dosent let you change cam to far from stock without a major tune. i strongly recomend that you save to get a new prom burned for it. if you do that, then the opitions get a lot bigger.

 

You can get one new lifter from most any auto parts store.

My last pricing of a full set from PAW was somewhere in the 150 dollar range. They are the house brand lifters but I'm sure they are just fine.

Good luck on your project!

 

That might be the stupidest thing I've ever heard.
A GOOD parts store should be able to get you a single Sealed Power roller lifter. Any GM dealership should be able to get you one lifter. Or you could get one good used lifter from a junkyard, or ask nicely and someone might GIVE you one. I've got a set of used roller lifters I'd sell cheap.

Going to a non-roller is a step backwards.

 

Buy one new roller lifter, use your stock cam (or a very similar one), buy some 1.6 roller tip rockers, and put some money into a better exhaust system.

Oh, and if you are going to replace the injectors buy some Ford SVO's: Bosch 0280150561 D9B 22lb/hr (pink tops) from fiveomotorsport.com

That's my two cents...

 

 

If you've got the camshaft out of the motor, you'd be stupid to put the same cam back in. At least step up to a cam with specs similar to a L98. A ZZ4 cam would be another option. GM offers other grinds too. GM cams from the dealer shouldn't run you more then about $150. Seriously, there's no reason to pinch pennies when you're already doing the labor.

Camshafts and heads are a few of the modifications that you'll actually notice, spend a bit more and get the good stuff.

 

Summit has a set of roller lifter for about $120.
The LT1 cam will work just fine and you can grab one for about $25.
I put one in my 305 with a set of the lifters from Summit.
I had a bad lifter and a bad cam!
The LT1 cam in not that big of a difference that the computer would tell.

 

Thanks for all the help everyone.

I ordered a new lifter from the parts store. A friend gave me a LT1 cam he ordered to replace the one in his firebird, so that covers the cam selection i was having trouble deciding on. Ive started porting the intake, when thats finished ill be porting the heads also.

 

with that you should see some soild performance increases. good deal
are you going to go with some 1.6 rockers?

 

Take a look at these rockers:
http://store.summitracing.com/partde...5&autoview=sku

 

I'm going to stay with the stock rockers for now, since thats something I can upgrade in the future.

I'm building this car to loan to my brother since he threw a rod cap through the block on his. Thats why I'm trying to get it done quickly and as low cost as I can.

Right now I want to get engine internals built, but everything that can be added later im holding off on.

Can anyone recommend a good place to buy a rebuild kit for my 305? Summit and jegs both have them, but the highest compression rating is around 8.6:1 with 64cc heads. I know my heads are 58cc and that will bump the compression up, but im wanting something in the area of 10:1. Even with the smaller cc heads I dont think i will be much over 9:1.

 

Please dont go back in time and resort to a flat tappet lifter cam. They are correct parts stores or GM can get you single ones. I had a 305TPI in my 88 IROC and I cammed it with a Comp Cams Extreme Energy roller cam (212/218 @ .050 .488 .495) The car had an awesome idle and with a few other mods, JET HOT coated Hedman shortys adj fuel regulator, and some other stuff. The car went awesome and no one could believe from the sound the rump in hte cam and the way it moved that it was a 305.