I have another thread around here about me contemplating a 355 or 383 Build. I have since decided to go the 383 route. Mainly due to the fact that my combo of parts should all make peak power around 55-5800RPM. So it will be a fully forged 383 with AFR 195 Comps. Cam somwere in the 230 duration and 560 lift on a 113 LSA. Also it will have an Extreme ported plenum, SLP runners and TPIS lower, both siamesed as much as possible, and port and gasket matched. Dyno Dons getting some pretty darn good flow #'s with his heavily modded TPI, So im sticking with it. Of course all this with the help of my Procharger P1SC. I also realize (correct me if im wrong please) but when incorporating boost into the equation, it helps push the LTR setup to make properpower. And not choke it, as it would on a N/A engine. I read a quote : its easier to blow air thrue a small straw, then suck it thrue the same straw.
OK, so here's my question. Do any of you fella's have the same or similar setup? What are youre E/T's ? HP + TQ#'s ? Ive been doing TONS of searching, and have come across alot of these combos. But nobody with any real world #'s or times. I would also appreciate feedback, tpis and suggestions on this build. I have yet to order a single new part. So all reccomendations will be taken seriously.
PS, The rest of the driveline and suspension is all taken care of. So i just need help and tips on the motor build. Thanx.

 

Push or pull is the same pressure drop. That quote is not correct.

Is the flowed/ported LTR setup optimal for your 5800 RPM redline? No.
Will it work decent at the top end and give more torque at lower RPM? Yes.
It depends if you want max. peak HP or more average HP.

 

I want the car to be a monster off the line to the 1/8th. Im not concerened about a tenth or two in the quarter mile. Id rather smoke my competion on the street, not the track. So yes, i guess more average HP.

 

Actually, technically, the quote is correct, it is harder to suck than blow, the human body cannot generate the same pressure differential both ways. The example is just misapplied here, since as far as an engine is concerned, pressure differential is pressure differential, fairly heavy metal parts don't care, at least not in the range that we're talking about.

As far as the rest of the question, there is no real reason why it would be significantly different than any other engine combination.

 

NY3 contact AC on here is as a very similair setup he'll chime in here soon i'm sure he can a couple of your questions for ya

 

Mark,
You got me. Yes, the quote is right about the human body. Like you said, it has nothing to do with an engine. What do you think about the 230* cam? I was thinking something around 226* with his setup.

 

After countless hours of research here, I have decided to go with the FIRST Injection system. Now after i figure out what the best cam will be. Ill be about done with my plains. My fabricator is also going to fab up a new intake tube from the intercooler up. ( to fit the monoblade TB)

So i have a new question- Would it be beneficial in any way to get my supercharger ducting ceramic / jet hot coated? or can this hurt performance by retaining heat? or would it dissapate the heat?

 

Go with teh FIRST TPI, get a cam in the 220's duration and blow alot of boost through it. It will go fast.

Dont need RPM to make power with boost although it reallly helps make more power with less boost. How fast do you want to go? Shouldnt have any problems making over 600whp and sneaking near 9.90's in the 1/4 mile at over 135-140 mph

Granted I have a single plane on my 401 but it only showed peak at like 5200 rpm which is TPI area... I made 640whp on 12.5 psi on a mustang dyno through a loose converter. Expecting much more once i get the bugs worked out. I think a blown/turbo FIRST TPI is a good street choice.

Torque is going to be nasty tho, and make it impossible to hook on the street when you get on it...just to warn you.

 

Thanx for the reply. I was really only aiming to be a low 11sec car. Mainly becasue its FULL weight street car. But i was also looking to make over 600 to the wheels. 1 more thing im having trouble with is selecting piston types + cylinder head cc to make the CR is should have. I was thinking 76cc heads with flat tops should put me around 9:5, And with being all forged should be good with 12-15pds ofr boost. What do u think?

 

Flat top and 76cc is around 9.7 to 1 i believe, alittle much for boost but it can take it. I'd just run a small dish and shoot for closer to 9 to 1 if you can, but mid 9's will work with moderate boost in the 10-14psi range I'm thinking. I've hit 18 on 93 oct on my motor at 9 to 1 compression, i'd hope 10-14 would work on 9.5-9.8 to 1 compression.

600whp is gonna be alot faster than 11's even in a 3600+ lb car. Unless your on street tires. You can make low mid 11's on motor with a 383, dont need the boost.

 

A flat top with 4 valve reliefs (around 7cc) wtih a .028" GM gasket, 4.030" bore, standard deck (.020" - .030") height, 355ci with 76cc heads will put the CR around 8.6:1 to 9.0:1

You can put in your exact numbers here:
http://kb-silvolite.com/calc.php?action=comp


EDIT: I forgot, you are doing a 383ci. Try again.........so that comes out to 9.1 to 9.6:1

 

Just going by my 383, i had zero deck and 5 cc valve relief flat tops, at 11 to 1 compression with 65cc heads. I was going to boost that with adding 75cc chambers but I believe it was 9.8 to 1 and still wasnt low enough for me. This was .041" gasket on zero deck

 

Well im going to go thrue everything with the builder when i drop off the block. Im going to try for 9:1-9:5.
And yeah well, I guess it will be a pretty fast car then. And yes it will stay street tire, until i put in a 12 bolt. But who knows when that will be.
I am going to miss beating up on 4thgens with my little old 305.. Now im hoping to start beating up on ZO6's and the like. Thats the point of this build. I dont want to fear anything that rolls up on me (on the street) and still appear basiclly stock.

 

That was one of my goals too, except you will get beat because you wont have traction haha. High roll speeds are your friend. Start playing with sport bikes

 

that's a loaded question... I don't think that we can really answer it without a clear definition of goals for this thing. I don't see any mention of powerband or anything else helpful to answer that besides the choice of the first injection setup.

you've got a bit of a funny combination to judge what other setups will do from. The 401 will make a cam act like a smaller cam, and then the tighter LSA (looking at your build thread you're showing a 233/233/112 cam) will make more power in the midrange then even the same cam with a bigger LSA. Add in that turbos tend to move things down in the power band also, well...

that's the other side of the coin... personally, for a street car I would pick something smaller and build something that will impress all comers. No one on the street can tell an 11second car from a 9second car, but everyone is impressed by one that will obliterate a set of tires at any speed you decide to put it to the mat. (oh, and it's fun also )

OTOH, if it's a track car, unless you have big, sticky tires and a well sorted suspension massive low and midrange can become a real PITA. for that matter, even if you do get things sorted then you have the problem of the insane cylinder pressures and torque making it hard to keep the driveline in one piece.

I'm hoping to have some time to tinker with a 305 in the next year or two (all the "you can't make a 305 run" and "what's the fastest a 305 has gone" threads plus picking up a project car with an only slightly smoking/tired LB9 have inspired me). I'm hoping to use a mostly stock long block, with just a cam change, maybe a little work to the cylinder heads and an intake swap (I just hate dealing with the TPI setup). I'll probably use the cam that I had ground for a 350 (224/224/114), but I'm really tempted to have something in the 236-242 range with 114-116LSA made for it just to move the usable power band up high enough that I can still make the power without relying on the high $$$ to hold it together (hopefully keeping the rpm in a range where I don't need $$$ parts to keep the moving parts inside the block).

 

Engines like that are the most fun. I was wondering why you had a custom made with those specs. Must be a roller, right? Non-roller off the shelf are available.
If your 305ci is a non-roller and you want hydraulic then maybe this will work for you. It is a $90 cam & lifter set. There are a lot of decent off the shelf turbo cams.

I think with a set of stock heads ported, LT1 intake conversion(keep your GM all GM), stock short block, and a cam change to the one below........you could do quite well with the 305ci. That was the plan for the one I have sitting in the corner of my garage.

Elgin, Hyd. Flat Tappet Cam & Lifter Kit, Chev SB, .487/.487
Chev SB
Lift: .487/.487
Adv. Duration: 303/303
Duration @ .050": 234/234
Lobe Center: 114
2000-6000, Rough idle, Good mid-range, Auto w/stall

 

Well it may not be apples to apples but a 383 and a 401 arent to far apart. Same cam in both motors wont act too much different, the 401 wouldnt peak as high by 200 or so rpm but its close. Stroke is the same just bore size is different so the cam timing events can be similar for both setups to accomplish the same thing.

My cam was originally spec'd for a 383 but when I told the cam guy I was going with the 400 dart block, he said you can run more lift with a higher ratio rocker but wont need to change the duration to accomplish my 5800 rpm peak hp range. But so far it looks like peak is well short of that 5800 mark but I have a bad converter in this setup so cant comment yet to how the cam is performing.

 

it's an '87 LB9, so it should be a roller. If it wasn't a roller then there are dozens of really cheap flat tappet cams out there off the shelf that will work, heck, summit has a 224/224/114 and a 234/234/114 cam+lifter kit for $89...

[/quote]I think with a set of stock heads ported, LT1 intake conversion(keep your GM all GM), stock short block, and a cam change to the one below........you could do quite well with the 305ci. That was the plan for the one I have sitting in the corner of my garage.

Elgin, Hyd. Flat Tappet Cam & Lifter Kit, Chev SB, .487/.487
Chev SB
Lift: .487/.487
Adv. Duration: 303/303
Duration @ .050": 234/234
Lobe Center: 114
2000-6000, Rough idle, Good mid-range, Auto w/stall[/QUOTE]

that's pretty close to what I was thinking about, but again, I have a roller block, and kind of seems a shame to get rid of the roller. I have an LT1 manifold sitting around also, but I also have a vic jr that I converted a while back to FI, and I trust the distribution better on it.