First off, i know the first thing that comes to your mind, "Why the hell did u mod a 305"? Id rather not go into that issue, and just stay on the subject . Here are my mods
TPI induction(MAF)Block itself is from an 87' TPI.
Bored over .30 305 roller block. 348 crank
The bottom end basically has the best parts in it. L98 Corvette alluminum heads, ported and polished, was refurbished, reused exhaust and intake valves. Lingenfelter cam part # 74211, Accel double springs,Titanium retainers,comp. valve locks, comp. pushrods, Edelbrock intake manifold,Ported Plennum,1.5 alluminum rocker arms,Reproduction distributor,w/ new aftermarket standard cap,Hypertech coil and rotor. AC Delco 7mm wires and AC Delco plugs. Cloyes timing chain, Ford SVO 19# injectors,Edelbrock TES headers to single 3" collector to 3" Catco converter to Flowmaster 80 Series catback. Im not running emissions, so the only pullies im using are the crank,waterpump,alternator and power steering(not underdrive pullies, just stock) 180 degree thermostat,Fan rigged to stay on while motor is running. Car has a T-5 manual(88') with Zoom multi friction clutch, Stock suspension except for V6 springs and rear 3.23 gears. I took it the track 3 weeks ago and the worst i did was 15.8 at 86mph and the best i did was 14.8 at 94mph. with 2.37 60ft times. Is my setup wrong somehow? The pistons i ordered if used with stock heads should be 9.6:1 but since im using vette heads(88') are the CC's the same as the LB9 heads? Im still using stock fuel pressure regulator,stock Runners and Stock 48mm throttle body, Should i go to SLP runners and 52mm throttle body? Sometimes at idle the car runs Lean, then at WOT it runs stoich. Car does not bog,or have any idle issues, Runs strong and hard im just curious as to know if my setup is wrong. BTW on the track i ran on Steet radials and had traction issues on 1st gear. Any help on what should i do would be appreciated. I also have a new fuel pump and new filter. Thanx for any info.

This is the specs on the cam

Model Number .05" Duration 1.5:1 Lift Lobe Sep. Notes
74211 211/219 .503/.525

Im using stock Roller lifter(was in great condition)

This was all done with factory chip and computer, I heard lots of people spending money on custom chips only to go back to the factory chip.

[This message has been edited by BlowBye (edited July 14, 2002).]

 

the compression is going to be the same assuming the same thickness head gasket and the chambers of the heads were not ported. but it will act like 8.5 to 1 engine because they are aluminum and give off heat much faster. also the porting might be a little excessive for the small 305 a set of iron vortec's milled to 58cc would probably work better. the 48 throttle body is fine. i would use lingenfelter runners and not the SLP's. a fuel pressure regulator is a good idea but you really need a custom chip.

 

Im not debating with anything u said, but i have a question, Why should i go with the LPE runners instead of SLP's? Im gonna go with the Fuel pressure regulator, Would u possibly know of a place that has good responses? The only man i know is Ed Wright, but i've heard bad and good responses.

Oh yeah the combustion chamber was slightly ported, In the future i was gonna install an ATI procharger but i was sure it wasnt gonna lower the compression that low since the heads are alluminum. Head gasket is a Felpro 1010 gasket.

[This message has been edited by BlowBye (edited July 14, 2002).]

 

Wow, that's not good. I've seen mild bolt on 305 TPI's, and even L69's run about the same, so something is definetely off. I think the vette heads are 64cc vs 59cc for 305, so you are down on compression. #'s on the cam aren't too big, but longer duration combined with less than optimal compression will result in loss of torque. 3.23 will not be enough with the short cubes. L69 came with 3.73.

If you give it too much rpm on launch, you spin and get an ok mph (94). Slow launch and you get the bad mph. You need to work on traction so you can get off with a higher rpm launch.

Lastly, the small bore on a 305 will shroud the bigger valves in the vette heads, so I think the potential of the worked heads isn't coming into play much.

I have an mostly stock 89 Formula 350 twin cat that's run a best 15 flat at local track (about 14.3 corrected). I've driven friends well modified 305 5 speed fbods that were just as quick, but were more fun to drive than my a4, and seemed a lot zippier, so the potential of your combination is excellent. Now that you've got the major investment in the engine done, you just have to optimize and I can see you running low 14's/high 13's.

 

Do u guys think i should go with 3.73 gears? Its a stock 10 bolt 7.5 from a 92'camaro rs which has a v6.

Lastly i plan on ordering BFG Drag radials, size is an important thing and i plan on mounting them on 15x7 or 15x8 rims what size would u guys recommend for the track. thanx

 

Aluminum corvette heads were 58cc. The cast iron stockers on 305's I thought were also 58cc.

The restrictions in your setup are the TPI, the fact that you are using a factory chip, and of course traction.

The TPI: needs to be siamesed so that you can get a lot of air moving through it. The whole thing needs to be opened up.

The Chip: When people "said" they got a chip for their car and were not happy, it was because they got an off the shelf chip. Those are junk and are quite good at what they do, deliver no performance gains at a high price that people will pay. The best chip is one that you get custom done for your application. Trust me, you won't go back to the stock chip. Here's a lil example. I have an 89 MAF car. I have 2 chips I can use, the stocker and one from an 87 Vette. With the Vette chip I picked up over 2mph at the track and a whole .1 . Thats not bad considering that the car runs like crap on both chips. Just imagine a chip tuned for my car specifically.

Traction: seems you have that figured out.

 

You simply have way too much cam for the engine and gears. You should be down in the .470 region for a roller cam on a 305. You have moved your hp and torque far to high up the rpm band. A shorter lift and duration cam, like a Comp XR 252, would get you through the 1/4 a lot quicker.

 

Are u serious? I was told by others that the cam is a great choice and LPE says that the cam i have is idealy for 305TPI with modified intakes and exhaust. Boy i hate to think i spent $375.00 on a cam thats useless for my setup

 

It's not a useless cam at all. But you need to work your intake over. AS&M runners (thunderracing.com sells them) are the best you can get for our setups. You HAVE moved your powerband up significantly which is why you need the worked over intake. Just porting your plenum simply isn't enough. Siamese the base (consider replacing it with an edelbrock).

[This message has been edited by Yellowknifer (edited July 14, 2002).]

 

Now im confused.
I know for a fact that im getting 3.42 gears, thats settled, So now im in a need of Runners, Done, Now i have the Edelbrock intake, Are u telling me thats not sufficient enough? Just to be sure should i stay with the 48mm throttle body or go with a 52mm?

 

Oh sorry my bad. Yes use your current baseplate and siamese the heck out of it. I'd recommend around 3" on every set of ports myself. I'd also port match your intake and heads if that hasn't been done already.

 

the reason i said the lingenfelter runners is because they are not siamesed the as&m or TPIS are fine too but cost more money and the little extra airflow is not needed the 305 is a small engine and must be treated this way. DO NOT SIAMESE THE BASEPLATE. this may work with a 350 but it will probably cause some revesion problems with the 305. 48 mm throttle body is fine same with the cam. for the chip you could try Z Industries in california. you might want to take your cover off the rearend and look first cause a lot of v6 cars had 3.42 gears.

 

Oh i know for a fact it has 3.23 gears. I cant seem to link to LPE's website, If it'll solve the problem i'll be happy. I hate the Edelbrock Headers, they just freaken leak and the bolts work themselves loose, so know i gotta get the fastners. Thanx for the tips guys, Last question for drag use, I have 15X7 rims what drag radial size do u suggest? i was thinking 275/50/15? but is this too big? What Psi would u have it at? thanx

 

ok the car itself is a 1992 camaro RS it had a v6 and auto 700r4, I converted to a 87 roller motor and 88' t-5 tranny.

Oh yeah its has a 10 bolt 7.5 3.23 gear rearend.

[This message has been edited by BlowBye (edited July 15, 2002).]

 

I deleted my post after I saw that you had already posted about the origins of the rearend.

I wouldn't go any deeper than the 3.73 gear.
TPI's don't like gear or high revs.
I have a 3.45 in my LB9 (215hp) 5 speed and I find myself short shifting (or feeling like I am short shifting)because I am into the rpms quicker than I thought.
With the 245/50R-16s 60 mph occurs exactly at
5500 rpm redline in 2nd gear. So my 2-3 shift is @ redline. Since the car doesn't make power above 4800 rpms I am not gaining anything by redlining it, just delaying the 2-3 shift until i reach 60 mph.
This works great if i am racing someone on the street but is hard on the car.
If I had 3.73's then my 2-3 shift would probably come @ 55 mph. So it wouldn't help on the street.
Especially since the car has all kinds of low end torque.
If I were drag racing with taller slicks there might be an advantage to the 3.73.