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355c.i LT1 head selection

 
Red2N
V-6 Camaros rule!
Posts: 33
Joined: 04/12
Posted: 05/05/12 05:33 PM

I have a 355 with a hot cam. my current cylinder heads are ported stockers,with a cnc'd intake runner 220cc i think, and stock valves. My question is would the 21 degree heads from trick flow enhance my performance? my plan is to have a 10sec car, with the hot cam and a little NO2 boost. I figure the better theheads flow, the smaller the shot I'd have to use to reach my goal. any LT1 expert advice would be greatly appreciated  

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pepsi1
V-6 Camaros rule!
Posts: 111
Joined: 09/11
Posted: 05/06/12 09:47 PM

Red2N

What is your future plans? Is it a daily driver? Street/strip?

You say a hot cam what kind of numbers are you talking about? Lift and duration at.050 not advertised duration that doesn't help. Who made the cam and a P/N?

I need some info as to what you have. What rear gear what transmission manusl or automatic. What kind of car? Something to go on.

I don't like NO2. You really need a low compression engine. NO2 does crazy things if not properly installed. In other words it blows Chit up...I would not use aluminum heads with it. If your stock heads have been modified that much there isn't band OTC head that will do any better.

Bob  

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Red2N
V-6 Camaros rule!
Posts: 33
Joined: 04/12
Posted: 05/08/12 06:58 AM

Bob

I plan to keep it a atreet car. I don't want it to be so radical that it will choke out at a stop light, so Ican keep the option of driving daily. If Ican clispe a high ten in the 1/4 it's still a 10 sec streetcar to me. I only want to hit that number once and from that point it won't see the strip...oter than from where it will be parked at the track.

As far as the hot cam goes, its the GM performance LT4 hot cam, pn 24502586, with 1.6 ratio rocker arms. I can't honestly say what the non advertised numbers on the cam is because all I know up to this point is the advertised information. The car, 94 camaro, is being put together by a rather crafty fella so it's probably going to perform better than advertised, even the deck has been milled a bit. He won't tell me everything..his slogan is, "mum's the word". lol.

The transmission is an automatic, 4l60, stage 3 or 4 if I'm not mistaken, and a 3000 stall lockup torqu converter. I was advised taht there really is not asignificant performance difference between, 3.42 and 3.73 gears,so I'll more than likely go with the afore mentioned. The heads have been modified, truth be told I know nothing about cylinder heads other than what I read. i've recently read about how cylinder head flow and engine CFM should compliment each other and too much flow could hamper performance, as well as too little. I have not read about anything closely related to this particular build. I do appreciate the advise on not using NO2 with aluminum heads and the fact that it could be disasterous. The pistons are SRP with a compression ration of 9.5:1..I think. I'm not interested in doing a cam change or anything at this moment.  

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Scott Parker
Moderator
Posts: 217
Joined: 12/07
Posted: 05/24/12 10:33 AM

That would depend on how good your current heads are. I doubt they are 220cc if they are stock casting. Elliot Port Works goes up to 208cc on their stage 3. To run a high 10 on nitrous with a conservative shot you'll need to be running a high 11 on motor. With a little bigger cam and higher stall converter my LT1 Formula went an 11.97 on motor, and later went a high 10 on nitrous. I'd establish a good baseline and go from there.  

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Scott Parker
Moderator
Posts: 217
Joined: 12/07
Posted: 05/24/12 10:52 AM

FYI compression isn't that big of an issue on the LT1 thanks to aluminum heads, reverse flow cooling and a sturdy block. 10-11:1 on pump gas with nitrous is no problem with a conservative tune.  

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pepsi1
V-6 Camaros rule!
Posts: 111
Joined: 09/11
Posted: 05/24/12 02:37 PM

Icon QuoteRed2N:
I have a 355 with a hot cam. my current cylinder heads are ported stockers,with a cnc'd intake runner 220cc i think, and stock valves. My question is would the 21 degree heads from trick flow enhance my performance? my plan is to have a 10sec car, with the hot cam and a little NO2 boost. I figure the better theheads flow, the smaller the shot I'd have to use to reach my goal. any LT1 expert advice would be greatly appreciated

I apolize for taking so long to get back to you:

In order to have a 10 sec. car in a quarter mile I'm going to need more info.

What kind of car are you trying to do this with?
Do you know the weight with the driver?

To get a 3200lb, car to touch the 11's your going to need 470HP.atleast

I sold my play with 1968 Camaro that was a race car all it's life. It was an original 375/396...Here's what it took for it to run 11:20's @122MPH.
It had a 402 BBC..What it made for HP I don't know..It was my having fun car...

The engine was not stock...It was overbored by .030. It was Balanced/Blue-Printed.  12:5:1 Speed Pro pistons...
Crane Cam that P/N 131131 608/628 It was really a 435/427 Cam. Matching Valve springs. Viton Valve Seals.
TCI TH400 reverse pattern.
Ger/All Aluminum Trans brake. But I never used it.(Trans changed do to a L/Knee injury)...It was a 4 speed origanlly..
GER 4500 Torque Convertor.
Car weighted 3200LBS. with me in it.
750CFM Holley double pump.with .110 Viton needle and seats both sides.
Holley Blue Fuel Pump,and Regulator
Edelbrock Victor JR.Old style.
Rec. Port Heads. Bone stock, Head #3856208..
5:13 Rear Gears
11.5" Wrinkle Wall Slicks..

Bob  

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pepsi1
V-6 Camaros rule!
Posts: 111
Joined: 09/11
Posted: 05/24/12 02:56 PM

You can see by my post what it took for my Camaro to be in the 11's I forgot to mention I had 5:13 gears and 11.5 wrinkle wall slicks. I put wheely bars on it as it scraped the rear bumper. So rather then ruin parts and maybe flipping it over. It had a 10 point cage....It was a real nice ride...

But I had a 1966 ChevyII that was my money car. That ran 9:40's..That was a race car all it's life also. I actually built a duplicate of Grumpy's old 331 Pro-Stock engine to keep it a Nostagic car.

So give us some info to see what we can do to help you go fast.and then faster..
Bob  

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Red2N
V-6 Camaros rule!
Posts: 33
Joined: 04/12
Posted: 05/25/12 01:11 PM

Thanks Scott, I will definitely double check the intake runner size. The guy building the engine has a 358 in his 93 camaro and has run as fast as an 11.8 in the quarter. I will defintely look into more cam shaft and a higher stall converter. I'm guessing Advanced Induction would be a good starting point?  

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Red2N
V-6 Camaros rule!
Posts: 33
Joined: 04/12
Posted: 05/25/12 01:20 PM

Bob,

The car is a 94 camaro. The only current weight reduction has been an UMI K member. It was originally a V6 car, and I weight 175lbs. As far as gearing goes, I was hopoing to be able to get by with something in the 3:73 range. I plan to buy 10bolt upgrades as well, posi, gears, axels and centersection cover, in hopes of helping my 10 bolt stay together long enough to reach my goal.  

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Red2N
V-6 Camaros rule!
Posts: 33
Joined: 04/12
Posted: 05/25/12 01:35 PM

Scott,

The heads are the stock design, circa 1997 z28. I read a little on LT1 heads and the book I read,Fourth Gen F-Bodies 1993-2002, stated that the intake runner port had to match the bore of the engine in order to maintain a certain ratio percentage of air flow or something like that...so I immediately thought the .030 over bore must have been carried over to the heads. The one thing i haven't researched was the original intake runner size on the 97 LT1. My curiousity for the intake runner size came when the engine builder told me their size, and I decided to youtube LT1  specific vehicles by head flow to get a general idea of how well I could expect the heads to perform; and as you may have guessed, it turned up nothing useful. The thing that got my wheels turning was the fact that the heads are still using the stock valve size.  

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pepsi1
V-6 Camaros rule!
Posts: 111
Joined: 09/11
Posted: 05/25/12 11:26 PM

Yeah induction is the key to horse power in any normally asspirated gas engine. In order to get flow from the heads you need a cam shaft be enought to help the engine pump. I don't think it's possible with a 3:73 gear. I would pull the cover on the rear. Because it has 10 bolts it doesn't mean it has a 10 bolt ring gear. Those are the smaller 7 5/8 ring gear.

I have an 86 Monte Carlo SS with 3:73 with a posi and that has the small ring gear.I put a shift kit in the trans when I bought it in 1985 new. It's still behind a 305 and it takes a hard shift but I don't know how long it will last?  

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pepsi1
V-6 Camaros rule!
Posts: 111
Joined: 09/11
Posted: 05/25/12 11:34 PM

Just because it's an LT-1 does not mean it has all the good pieces in it like the early ones. I saw enough of them blown up in cruisers. The bottom end is 2 bolt and the heads are junk. In fact because the cruisers idle for long periods of time they crack the R/Head and exhaust manifold. They run good because the cam. In fact I have a friend that has a 1984 Vette. I pulled the oil pan to replace the gasket. He thought for sure he had a 4 bolt block. They have 2 bolt blocks,cast cranks.  

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pepsi1
V-6 Camaros rule!
Posts: 111
Joined: 09/11
Posted: 05/26/12 10:33 AM

Red2n

I just came across some info you may want to look at: web-site www.cartechbooks.com then look under "STREET SLEEPERS". I actually saw this 4500lb. Gran Prix run 9.5 secs. He leaves with the wheels up and plenty of air under it. You can read his story as to what it took to get it there.

It really takes big everything. Big Cube engines, big superchargers, Nitrous,etc. It may be worth the $25.00 and maybe you can get some first hand information. That's all this Gran Prix isa stock appearing car!!!

I hope you check back on your Post...Good Luck...11 second street car is a nice fast ride. I can only say this do your racing on the track. Beit an 1/8 or 1/4 mile and have fun,but be safe...

Bob  

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Red2N
V-6 Camaros rule!
Posts: 33
Joined: 04/12
Posted: 05/26/12 03:09 PM

Bob,

Thanks Bob. I will definitely check out that site.  

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pepsi1
V-6 Camaros rule!
Posts: 111
Joined: 09/11
Posted: 05/26/12 07:28 PM

Your welcome.

Bob  

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