Help with 383 Build

[Scott Danforth]

Re: Help with 383 Build

the 4-bolt helps with loading if your building a lot of power. the center main caps have 4 bolts vs 2 to help clamp the crank in place.

 

[John_S]

Re: Help with 383 Build

The Machine shop did ask if I wanted to have it converted to a 4 bolt main. Everything I read on here said a 2 bolt main was fine. Does the 4 bolt really help with the balancing?

Wouldn't help at all with balancing. You can certainly go to 4 bolt mains, it won't hurt anything. For referance sake, the Merc 377 (no over-bore) uses 2 bolt mains, with a forged Lunati crank.

 

[pennyduke]

Re: Help with 383 Build

I did read about all this for about a year before I started. There was a thread where Don s talked about 2 bolt verses 4 bolt. I don't know if he mentioned the 383 motor but I don't remember him having a problem with the 2 bolt. My origional plan was to order the stroker block from summit already bored and clearanced but they are out of stock.

 

[joewithaboat]

Re: Help with 383 Build

If your block is already hone fit to your pistons, a two bolt will be fine. With the heads, intake, cam you are talking about It wont see more than 325hp/5000rpm.

The retro roller lifters cost more than the stock type rollers. Last time i bought some that was the big cost difference.

Should be a very nice upgrade!

 

[greg82255]

Re: Help with 383 Build

If your block is already hone fit to your pistons, a two bolt will be fine. With the heads, intake, cam you are talking about It wont see more than 325hp/5000rpm.

The retro roller lifters cost more than the stock type rollers. Last time i bought some that was the big cost difference.

Should be a very nice upgrade!

I'm using a 2 bolt main block. I was told that it would be fine up to 500 hp.

As far as roller vs flat tappet, it's the retro-fit lifters that are going to cost you the most money. The cam itself is around 300 but I paid $465 for the lifters. You will also need a bronze or melonized distributor gear and a brass-tip fuel pump rod if you are using a mechanical fuel pump. In addition, if that block has been decked and the heads surfaced, you may not be able to buy a kit with pushrods - you will have to measure the pushrod length yourself with one of the length checking tools from Comp Cams. That requires you to either buy a solid lifter or put a light weight test spring in one of the heads.

 

[pennyduke]

Re: Help with 383 Build

325hp was pretty much my goal. I still may switch the pistons to get closer to 9:1. I think I will also have it converted to a 4 bolt main for a little security. My other goal is to never have to put another engine in this boat.

Greg, Did you ever list the part numbers for your build? Thanks for all your help!!!

 

[pennyduke]

Re: Help with 383 Build

If your block is already hone fit to your pistons, a two bolt will be fine. With the heads, intake, cam you are talking about It wont see more than 325hp/5000rpm.

The retro roller lifters cost more than the stock type rollers. Last time i bought some that was the big cost difference.

Should be a very nice upgrade!

What do Yall think about this Cam? http://www.summitracing.com/parts/CCA-12-416-8/

 

[joewithaboat]

Re: Help with 383 Build

What do Yall think about this Cam? http://www.summitracing.com/parts/CCA-12-416-8/

I think with a 383 you could go one size up, but you need to pay attention to the clearances on the heads... guide to retainer.

That cam you are asking about will be a fine choice, run well, and idle almost stock.

here is the comp description... note you will need a thrust button and wear plate if you keep the early non factory roller block.

http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=168&sb=2

Or next one up in size...

http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=169&sb=2

 

[greg82255]

Re: Help with 383 Build

325hp was pretty much my goal. I still may switch the pistons to get closer to 9:1. I think I will also have it converted to a 4 bolt main for a little security. My other goal is to never have to put another engine in this boat.

Greg, Did you ever list the part numbers for your build? Thanks for all your help!!!

I have not but I'll get that list together and post it tonight. If you're going for 4 bolt mains and building a near rock solid lower end, just curious, why only 325 hp? With vortec heads and a good cam, you could easily get into the 350+ range. I was told I'd be around 400, but I don't think I'm there just yet.

What do Yall think about this Cam? http://www.summitracing.com/parts/CCA-12-416-8/

Looks fine - I went with the next one up. If you are definitely going roller, you can use the 270HR and it will still idle just fine - mine idles smooth at 600 rpm. I'm actually now wondering if I could have gone with an even bigger one. You just need to make sure those Vortec heads were machined for the extra valve lift.

Now that I have a Stainless Marine exhaust, putting on some AFR 195 Heads and a larger cam may be the next winter project. If they're all the same price, I'd buy with the 270 HR if I were you. What kind of exhaust are you running?

 

[greg82255]

Re: Help with 383 Build

Here's the parts list I used with part #s, most of which are from my invoice. I think I included most everything that was important. If something is missing let me know and I'll go find it.

SCT-9-350-3750-5700L Scat 383 Cast Crankshaft, 9000 Series
SCT-3-ICR5700 Scat 4340 Forged I-Beam Rods
FM-H890CP-30 Speed Pro Hypereutectic 4.030 pistons -23cc, full floating wrist pins
EPG-43M-139-30 Hastings Moly Rings
Rotating assembly I believe was balanced externally at the rear and internally in the front.

COM 12-417-8 Comp Cams XM270HR Camshaft .495/.503, 218/226@.050, 112 LSA
COM-853-16 Comp Cams Retro-fit Hydraulic Roller Lifters
MAN-22410 Manley Performance Valve Springs
COM 2100 Comp Cams timing set
COM 208 Comp Cams timing cover kit with thrust button - This is what joe is talking about in his above post. You also need a wear plate but I can't find the part # for some reason. I'll find it and correct this.
COM 7938-16 Comp Cams hardened pushrods 7.100"
PRO-66914 Proform Extruded Aluminum Full Roller Self-Aligning Rocker Arms 1.5 Ratio
COM 4607 Comp Cams bronze tip fuel pump pushrod
FLP-1003 Fel-Pro 1003 Head Gaskets


1986 block, 1pc seal, 906 vortec heads. Bore/hone .030, hone mainline, zero deck block, clearance block for stroker, build in oil clearances for crank bearings, all new bearings, core plugs etc, 3-angle valve job, surface heads.

ARP bolts throughout, Edelbrock Performer RPM Air Gap Intake, Edelbrock 1410 carb, Holley marine mechanical fuel pump, Stainless Marine exhaust, Delco Voyager EST ignition, original flywheel, balancer, coupler, flywheel cover, front motor mounts, other externals.

Did I miss anything?

 

[Tail_Gunner]

Re: Help with 383 Build

If your block is already hone fit to your pistons, a two bolt will be fine. With the heads, intake, cam you are talking about It wont see more than 325hp/5000rpm.

The retro roller lifters cost more than the stock type rollers. Last time i bought some that was the big cost difference.

Should be a very nice upgrade!

Jowie im puzzled here...325 from a stoked 350 and modern cam..the 270 should net him close to 400

 

[greg82255]

Re: Help with 383 Build

Jowie im puzzled here...325 from a stoked 350 and modern cam..the 270 should net him close to 400

+1.^^

 

[joewithaboat]

Re: Help with 383 Build

Jowie im puzzled here...325 from a stoked 350 and modern cam..the 270 should net him close to 400

He is not asking about the 270 he has said he was using the smaller 264...
He has said he is wanting to keep the C/R down around 9to1
Stock vortec's, 1.5 rockers
He has said he is using the the much more conservative performer intake...

You guys think it is going to make 400 hp? Sorry just dont think that is realistic. 325 might be low I should have said 350 maybe.
Ive been wrong before. Lol

 

[John_S]

Re: Help with 383 Build

I'd say 325hp at the prop, is about right. The Merc black scorpion runs 9:1 compression, vortec heads, with a larger lift cam than the 270, and MPI, and that is only 350hp at prop.

Cam: The duration at .050" tappet lift (intake/exhaust) is 222/230; and maximum lift with 1.5:1 rocker ratio (intake/exhaust) is 509/528. Valve lash is zero/zero and lobe centerline is 112 degrees.

Guys, this is boat is probably 6K lb or more loaded. Why push the powerband above 5K?

 

[greg82255]

Re: Help with 383 Build

He is not asking about the 270 he has said he was using the smaller 264...
He has said he is wanting to keep the C/R down around 9to1
Stock vortec's
He has said he is using the the much more conservative performer intake...

You guys think it is going to make 400 hp? Sorry just dont think that is realistic. 325 might be low I should have said 350 maybe.
Ive been wrong before. Lol

I was more suggesting he switch to the 270 which would put him closer to 400. I personally don't see any reason not to - they're the same price, so one could argue that it's free horsepower . With the performer and the smaller 264, you are probably right, 350 or so hp. I'm only going on what I've learned in the last 6 months, a large portion of that from you Joe. Lol

 

[joewithaboat]

Re: Help with 383 Build

I'd say 325hp at the prop, is about right. The Merc black scorpion runs 9:1 compression, vortec heads, with a larger lift cam than the 270, and MPI, and that is only 350hp at prop.

Cam: The duration at .050" tappet lift (intake/exhaust) is 222/230; and maximum lift with 1.5:1 rocker ratio (intake/exhaust) is 509/528. Valve lash is zero/zero and lobe centerline is 112 degrees.

Guys, this is boat is probably 6K lb or more loaded. Why push the powerband above 5K?

That's a big boat...

If your getting another block, you might consider a "400" based small block might get you a little more grunt down low.

I'd build a long rod 406ci

 

[Tail_Gunner]

Re: Help with 383 Build

Hmm we all on the same page here

http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=202&sb=2

 

[joewithaboat]

Re: Help with 383 Build

Hmm we all on the same page here

http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=202&sb=2

That's the one we are all trying to pick for him.

He is however saying he only want's to go with this...

http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=168&sb=2

 

[pennyduke]

Re: Help with 383 Build

That's the one we are all trying to pick for him.

He is however saying he only want's to go with this...

http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=168&sb=2

I'm pretty much asking you guys to tell me which Cam to use. All of you have way more knowledge than me about cam choice. I do like that Cam now that I see it. The heads are already finished with the upgraded springs. Will those springs work with the cam you guys are suggesting?

greg, Thanks for taking the time to post all the part numbers. For now I will be using the Stock Exhaust stytem.

 

[Scott Danforth]

Re: Help with 383 Build

I would go with the 270 myself, however that is a bigger barge than I am currently running.