Scania

So the car is getting faster and faster .
This is the mods so far:

1986 305 tpi block borred 030 and the crank grinded 010
The heads come from the old 1988 305 tpi
Sealed power pistons and rings and pushrods
Summitracing lifters
Summitracing hydraulic flat tappet cam lobeseparation 112
Lift Intake@420 Exhaust@442 Duration Intake 204 Exhaust 214
Flowtech hedders with thermotech wraps and 3 inch exhaust all the way , airfoil in throttlebody
AFPR at 47 psi, Custom made prom, tb coolant bypass and kn airfilters
I just bought a pair of Arizonaspeed and marine large tube runners and ported the intake and ported the plenum.
Waiting fo summit to send me the 1.6 roller rockers
I have also installed Transgo:s shift kit in the thm 700-r4
Anyone care to take a guess on how much HP the engine puts out ? People ask me all the time and i have no idea. That would help me alot.

Some pictures of the engine during the build











The new black powdercoated AS&M large tube runners








I hope to get enough time this winter to change the rear axel , a have a used one lying in the garage and im planning to get a 3,42 or 3,73 , i havent decided yet.

1987earthquake

iTrader: (5)

Where did you get the valve covers from?

1987earthquake

iTrader: (5)

Also did you powdercoat the runners yourself? if so how

Scania

I got the valvecovers from summitracing , they are made by GM Performance and the nice filler cap from Classicindustries.
No i didnt powdercoat the runners myself.

90 white Z

I think the at the crank you are probably making around 275-290 hp. but thats just a guess. But anyway that is an awesome 305 and once you find out exactly what kind of numbers you are putting down be sure to tell us

Scania

Yepp i sure will, i have tested the car during the summer without the large tube runners (used the stock ones) and wow the car is fast . Hopefully it will be faster when i finished porting the intake and with the AS&M large tube runners.
And i hope to get the new rear axel in place during the long winter.

3rdgenZ

iTrader: (1)

and thats a lot for a 305.
might i add that is a very well balanced build up. nice cam and nice mods.
the only thing holding you back would be the heads. those runners out flow those heads ten fold. but i think even still you should be in the order of some nice 13s, given it gets a good tune.

Scania

Yeah i hope to make some good runs at the 1/4 mile next summer.

mnorton

The power that you get will have a lot to do with the custom PROM.... Also depends a lot on the compression ratio. What head gasket did you use? Are the new pistons going to give more compression than stock? Did you have the block decked?

I'd say that with a static stock compression ratio of 9.3:1, and stock heads, you might get up to 285 HP max, 240 HP min, at the flywheel.

I think that it will also take more fuel to get more HP, (I'm guessing that you still have the stock fuel injectors). I hear that the stock 19 LB. injectors with ~54 psi fuel pressure can get a 305 tpi roller cam engine up to 300 HP with ported stock heads, stock pistons, and using just a little bit bigger cam than what you have now.

Scania

Ok, youre right because im looking for 350 injectors , i guess they are 22lb.
I should have a slightly higher compression since i "shaved the heads" a at local machineshop last year. The headgasket is a felpro standard gasket.

mnorton

You will need to get more flow through the heads before you will need bigger injectors.

Scania

Ok so the injectors are not the problem rigt now, good then i dont need to waste any money on these. I mean if im almost get 290 hp then im very pleased with that.
Is it possible to find aftermarket heads that work with my stock ported intake or is the only possibility to port my stock heads ??
The Vortec heads needs another intake than the stock one , right ??

Another question . Can i use the 1.6 rollers on my stock heads and the summitracing cam or should i use the 1.5 rollers ???
How much extra hp will i get from roller rockers ?

tenpin842

I have LT1 24# injectors in my car. Stock heads. My 305 runs just fime with a custom tune.

mnorton

I agree that you can use the bigger 22/24lb. injectors with the stock heads, but you do not need them, and I will say that you will get no gain by using them. Not until you can flow enough to NEED all that extra fuel, and that means heads with more flow than the stock ones will supply. Still I think that you may want to have the stock ones rebuilt at the very least. Tenpin re-used his old injectors and they leaked badly..... That's why he has the bigger 24lb. injectors now. If you have the cash buy some Ford SVO's, they are a very popular choice.

There are only a few aftermarket head choices for a 305 TPI. If you need to comply with smog laws and need to keep the EGR valve, World Products makes the 305 S/R Torquer. It has the bigger and better designed back cut stem 1.94 intake valve, and flows pretty well for a daily driver setup. The exhaust ports on these heads need to be opened up to flow well. They also need some pocket porting done in the bowls, so they are not really what I would call plug and play.

Lots of people use the Aluminum Corvette heads, but it seems to me that they need to be milled a bit to get down to a stock volume 58cc combustion chamber. They do not have an EGR valve, so were not an option for me here in California.

I found that by the time you do all the needed upgrades and modifications to the stock heads, you may as well just buy new ones. The cost is about the same.....

I think that there are a couple of other brands too, maybe Holley, maybe Trick Flow.

The Vortec's do need a different intake.

Roller rockers will get you about 5 HP over the stock rockers. 1.6 rockers will help if the cam lift is less than what you need, but why not just get a higher lift cam in the first place? Also, with Rollers there will probably be a fit problem if you use stock center bolt valve covers. I think that you have to modify an oil splash baffle inside the cover to get them to clear. Maybe yours will clear though....

I think that your new high flow runners will not perform well until you improve the head flow. A stockish 305 TPI just won't use the extra air. You may even loose some intake velocity if used with the stock heads....

Do a search and I'm sure you will be able to find something that will work for you.

Your engine looks pretty sweet so far....

Scania

Ok thank you very much for the answer , always good to get some new ideas. I will probably port the stock heads but who knows what the future will bring.
I dont think there will be a problem with the roller rockers, im going to buy the narrow centerbolt ones.

TCH

Hi,

Can you explain what you mean with the statement about Vette alu heads? Stock 113 Vette heads have 58cc comb. chambers, why milling? EGR valve? Vettes using these heads also have EGR valve, its is there under the TPI plenum. So, please clarify, i didn't understand what you mean.

1.6 rockers under the center bolt covers? Yes, narrow models are needed and you must grind the drib tabs under the covers or they will not fit. I am running Crane gold 1.6 RR's under my center bolt covers and had to do some Dremel work to make them fit.

Scania

I have aftermarket valvecovers and they should clear the rollers . Anyway GM Performance claims that but who knows.

TCH

Yes, I was talking about the stock covers. But, make sure anyway before turning the key or unpleasant sounds might appear

Scania

Yeah i sure will.

Scania

I also need opinions on the rear axel, should i go with a 3,73 . Im afraid that the 1:st gear would be just insane with that ratio. Should i go with the 3.42 or something.
Please let me know because i need all the opinions i can get.

3rdgenZ

iTrader: (1)

i have a moded 350 with 373s. i must say it is the most gear i would put in a TPI. the first gear is a little short, but other than that 2 and 3 pulls really hard. . but, because i like to drive my car a lot, if i had to do it all over again id pick the 342s. in short if you drive it on the road a lot 342, but if performace is your calling 373s is the most you will need.imo
Note: with the 373s dont look for top speeds over 130-140. and in a race after 125ish it's just about out of breath. but in a TPI you should know that.

tenpin842

I love my 3.73 gear. I wouldn't have gone with anything else. Plus in the 1/4 mile your still in 3rd gear. I must say 3rdgeZ is correct. 2-3 gears you can feel it pull really well.

mnorton

It seems that you are right about them already being a 58cc combustion chamber. Still it seems that I read that the EGR setup is different than on a stock 305 Z28 TPI.... No EGR passages milled into the heads?

TCH

EGR passages inside heads? Didn't know such beast existed, but OK I guess I don't know everything.

EDIT: now I got it. It was explained in Tpi FI swappers guide. So, EGR gases are routed differently in early TPI iron head cars and alu head Vettes.

In Vette L98 with alu heads there is a separate EGR tube that comes from exhaust manifold to TPI base near distributor but the EGR valve is still located under the plenum.

Well, you learn something new every day.

Scania

Yeah thats why im looking at the 3,73 , the axel has a 2,73 right now . I know you have to order a special carrier or something if you have a 2,73 axel. Anyone got the partnumber on summitracing ?

Drac0nic

If you've got a ratio at or below 3.23 you have a series II carrier. If you have 3.42 and above you've got a series 3 carrier. I believe Richmond Gear makes gears in higher numerical ratios for series II carriers as well, but don't expect an OEM set to work. Engine Analyzer seems to be fairly consistent on your HP estimates btw, I've played a lot with that cam in it. I wanted to use the 204/214 cam but cost is prohibiting me right now. I'll be keeping an eye on this combo to see what kinda numbers you get, my setup is similar besides I'm gonna run Megasquirt, keeping the stock cam and runners. Should give me a good idea of what I'll get when I step up to the plate for the cam.

Scania

So the plenum is finished and now im going to port the intake , Im going to start tonight. I will post some pictures later.

Im trying to get new gaskets for the AS&M runners but so far nothing. They seem unwilling to ship them or something.
If someone will help me and you got an paypal account i will pay you for the help.

3rdgenZ

iTrader: (1)

are you porting the lower base?

Drac0nic

Hey, just a thought go to the track after you get your car together, see what MPH you run and see what you're gonna do mph wise before getting gears.
I appear to be getting the same cam, I'm giddy about it. Then again I finally got #3 running right on an engine stand only had to adjust the valvetrain 3 times to get it to fire. I only have a bunch of ECM and tuning issues to work out now. If you have stock heads and my ported 416es turn out to be decent, I suspect I'll be near 300hp. Engine Analyzer backs me up on this. I'm running a pretty thick HG though so I've got about 9.2:1 if the stock CR of 9.5:1 is correct. If you need gaskets Autozoo or Orielly or most part stores can get the Mr. Gasket 146 gaskets that are for large runners. The holes are ~1.75 inch diameter. After I hogged my base out the stock felpros were way too small, and even the stock gakets seemed on the small side IMHO.

Scania

Ok so summit partnr mrg-146 are the gaskets im looking for ?

Drac0nic

the plenum gaskets area bit bigger but the base gaskets are WAY bigger. Here's some of mine installed. Those runners are very heavily ported, so it gives a good idea of how big they really are. MRG-146 is the number that I used, like I said even a local store can order em for you and save you some coin on the shipping probably. Mine were $20 no shipping from autozone.

MARO-MAN

You wouldn't happen to have any pictures of the intake before you ported it? Or maybe a picture of stock gaskets compared to the bigger gaskets? Something to give a newbie an idea of how much material there really is to port.

I actually like my 305 and want to keep my Iroc a 305. So, its nice to read about your build. -Nick.

Drac0nic

Intake porting
There are a buncha pics here, before and after. The gasket it's self seemed to potrude into the runner almost 1/16th to 3/32 on each side as well, but it was where the "lip" was. The base almost is almost 1.625 diameter in the ports after the work is done.

Scania

Some new pictures, the intake is ported now and i also opened the plenum even more . I hope to get the engine started this weekend. Cant wait to test drive it.
I also had problems with the large tube runners, the two lower bolts need to be alot shorter than stock so it took me a couple of days finding the right size bolts.
Soon i should have a pretty fast 305 tpi, i borred it 030 so how much larger is it now ? 307 or what ?

tenpin842

awsome pics! looks really good.
Yes I had to jump up to a series 3 carrier, Cost me a lil over $800.00 for a Richmond gear and a series 3 carrier. Plus the kit, and all the gear lube, and posi lube included.
But I like the 3.73

D's89IROCZ

Basing on the cam you have is smaller than the 1989 stock L-98 cam . I would say no more than 225hp to the rear wheels . I know a guy who had the same setup ( wiht the bigger L-98 cam) SLP runners. SLP headers , pullies , and all free mods and tuneing. It got 227 rwhp . You have a great base to start with though . But I would pick a bigger cam if you don't mind getting into prom burning.

Scania

Well how much does the stock L98 cam lift ? This one lifts 420intake and 440 exhaust. I guess i will have even more with 1.6 roller rockers.

Scania

I guess next step is to find some good heads frp the engine. I know i can get Vortec heads but they will not fit the stock intake any other brand ? Or should i look for older 305 heads maybe the have better flow.
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Oh i dont mind getting in to Prom burning , we made a custom one for my car but now we need to make another one i think. I have to testdrive the car first before i make any changes.

PneumaticTire

thats a sweet engine you got there. wish mine looked like that/. let me in on the details about them plug wires and where you got them. I need a good pair of header wires.

Scania

I got them from summitracing , Accel steel braided wires. They look really nice , i also got the wire separators from summit.

87turboGN

how am i looking? My first TPI rebuild,got bored with my 10sec Buick,decided to waste some time doing this 305 TPI...

Scania

Wow looks really nice , what have you done to the engine ?

87turboGN

Just a rebuild,new crank,rings,ported heads,Some moron bypassed the heater lines into the factory oil cooler lines.What a f**King idiot....All fixed now,cant wait to drive it,5 speeds are fun...

Shadygrady

iTrader: (3)

the vette alluminum heads dont have to be milled.Im running them with L-T4cam and 1.6 full roller rockers.The 113 heads are the same as the zz-4 heads and they work fine with the 350 and my compression is around 10.5 to 1.Ive had no probs and it makes over 300 hp.with my roller rockers i had to get the tall vlve covres.The stock ones would not even touch the gaskets.but with the alluminum heads youll need guide plates and hardened push rods

90_T/AGTA

Looks really good

Scania

Thank you !!

Joes1wood

I know this is the fuel injection board, but does anyone know if the Corvette 113 aluminum heads will work with a 1985 LG4 305's stock EGR?

mmyers_417

It would be a 310