383 build spec help needed
 

Need some good practical experiance compression and cam help for a 383 4x4 build. I was hoping to go 10:1 but am having doubts about that. I want to run 87 octane around town/hwy and premium when I work the truck. Application is a 1989 K1500 regular cab- 7200lbs I think. Existing engine is a 355 that was done a few years ago and now showing mechanical/oiling issues but reasonably happy with performance, it was pulled and is at a shop now being gone through as I write this..... it MAY stay a 350 if the piston/bore is in spec but the decks were not even bank to bank (zero on one side). Seriously thinking on an up size. The truck has a built 700R4, oe converter, 3.73 gearing, hwy cruz 60mph OD 1700rpm, D 2400, 30mph D 1400rpm. I see GM truck orientated LS engines are around 9.6:1, I had a vortec headed 355 that was 9.5:1 with no issues using regular- I figured alum heads would allow me a 1/5 point up. Using Dynamic EFI right now. Still digesting Grumpy's advise was unwilling to go down in compression but now am thinking more along the lines of a powertrain that is less of a hassle and more of a good drive. Anybody use Evans coolant with good results regarding preignition resistance- or would this be considered a band aid instead of good engine design.
Just want a good torquey engine that will give a new truck Hemi a good scare but not willing to have a peaky pita.

Have AFR 912 heads on the 355, FIRST intake, existing Mahles are 9:1.

http://www.airflowresearch.com/index.php?cPath=24_117
https://www.firstfuelinjection.com/services.html
http://forum.grumpysperformance.com/...p?f=44&t=10448

My problem is understanding DCR vs SCR and my concern on performance on 87 not willing to use premium unless when needed- a car I wouldn't worry about but this thing is hard on gas as it is.

Some roller cams I'm considering which are all in the same class- billet is likely overkill but I hear about good quality on the Jones:

FlowTech(355) 210/214-525/530@110 in truck now- slightly noisey
Crane- 109671 216/224-509/528@112 small base circle, $440 billet
Crower- 00464 213/221-505-525@110 endurance racing lobes $315 cast
Mike Jones 220/224-510/510-@114 $440 billet
Howards 219/225-510/525@112 cast
Bullet 224/224-530/530@112 billet $415

If I stay with a 350 9:1 I'm looking at:

GM 12370845 214/224-488/509@122 same as Crane 109821 $250

Spec's aside I'm trying to find a top quality cam easy on the valve train- Comp is excluded for my own reasons. Isky, Erson, Engle don't have good sites.

Thanks

Re: 383 build spec help needed
 

Question.Is a separate gas tank and 100 shot nitrous out of the question??. Be aware for them to work properly they have their own outline in planning a build.

Re: 383 build spec help needed
 

Keep it safe, 9.5-9.8 to 1 is not bad with 87 with aluminum. A 383 with those heads will be a real stump puller. You can likely get 10:1 to work with one of the bigger cams but it may be more sensitive to tune and really wouldnt make a huge difference in power

All those cams are close. Dont think you need billet core. Low rpm deal and less aggressive lobes use less spring pressure so cast core will be fine. I like jones and bullet cams.

Re: 383 build spec help needed
 

Just so we're on the same page- this is a daily driver- truck, no NOS no racing.

I know you can get fixated on compression and for 0.5-1.0 I don't think there is allot on the table. I'm think 9.5-9.8 would do as well as well. Bullet offered a single pattern which I'm interested in $415 for steel which is all they have in cores right now. I think Lingenfelter had a few like these?

Re: 383 build spec help needed
 

Talked to the owner today- good talk and now he has a better understanding of what I want as opposed to a more competition oriented build- looser tolerances. He wants to go KB or some other hyp piston dished, I've always run the D-dish- much difference in quench vs performance?

Re: 383 build spec help needed
 

Have block decked to .010 or less and run standard .030-.040" gasket. Mls is nice.

Keep the quench/squish height to around that .030-.045 range and it be fine

Re: 383 build spec help needed
 

The decks will be zero'd and he likes a fel pro gasket with fire ring reinforcement- I was using gmpp .028 gaskets with no problems and requested the mls for my winters (alum/steel movement) but he said the mls seals the fire great but he has had customers with coolant seeps. The piston question was reverse dome vs full dish- my reading hints that the dish makes better power.

Re: 383 build spec help needed
 

Which brand mls? Some of the felpro ones i heard about seeps. I never had any with the two i used but i now use cometic. Need a good flat finish on head and deck

Reverse dome that mirrors the chamber is best. I dont think you'll notice a huge difference either way with afr heads

Re: 383 build spec help needed
 

Sounds to me like he is a fel pro shop- so your likely in agreement. A good composite will do as well. Depends on application.
He seems to like the Speed Pro or KB (more the Speed Pro)- I have Mahle D-dish in there now but the previous shop has 7 a little loose, so stepping down and will hone to size. He did say the Mahle skirts were very short and for this truck app he'll look for a proper skirt.

Re: 383 build spec help needed
 

We had KB Hyper-eutectic pistons in our 388. Flat tops with Bowtie heads with 65cc (measured) combustion chambers. Gave us 7 great years of racing and when the motor gave up the ghost the pistons were still in good shape. Not the compression range you want to be in but just giving you our experience with KB's. Get the right dish to achieve your desired 9.5-9.6 compression ratio with the heads you have.

Definitely want to watch the valve overlap in your cam selection. Too much and you wind up with a mid to upper range cam which is more suited for racing than street driving or towing.

Re: 383 build spec help needed
 

I had KB D dish 2 engines ago- seemed to work OK, looking at a 9.8:1 Speed Pro with conventional dish. And the builder like the Crane 109671 but wants to use 1.6 rockers- I would prefer he gets the lift he feels he needs with 1.5's.

Re: 383 build spec help needed
 

1.6's were great for flat tappet cams when you couldn't get the lift rates you wanted do to design restrictions on the lobe angle to lifter bottom interface. With roller lifters you can get those faster lift rates with out 1.6 rockers. I would think with a street motor you could get the lift, duration and lift angle you want with 1.5 rockers and a roller cam

Re: 383 build spec help needed
 

Whats the big concern with 1,6's?

Re: 383 build spec help needed
 

Don't know- I was told they are mechanically louder than 1.5's, and if you're buying a new cam why bother. This shop still wants to use them on a mild roller as I have both ratios in hand anyway and he says the AFR will the lift anyway.

Re: 383 build spec help needed
 

He also wants to use the full dish Speed Pro pistons- I would really prefer to use north american or european manufactured products- the existiing Mahles spec at .0025-.0033in piston to wall, 7 cylinders came out .005in. Hypers spec at .002in. Bullet got back to me with a 218/222-530/530@112 with a easy lobe. No 4/7 swap cores available.

Re: 383 build spec help needed
 

I have no problems with 1:6 rockers if you already have them or don't have any roller rockers and had to buy new. My only comment on it is if you already have 1:5 and are buying a new came anyway why buy new rockers when you can spec the cam to what you want in the first place. There are exceptions though but I don't know why it is necessary in the OP's application.

Re: 383 build spec help needed
 

I have a set of both- 1:6 Crower SS, 1:5 Comp Pro Mags, I prefer the Crower quality but the SS is heavier. This isn't an issue really- the shop is free to use what they feel is right for the app.

Re: 383 build spec help needed
 

Yeah dont worry about rocker weight for this application

Re: 383 build spec help needed
 

How do you like the Sealed Power hyper pistons (DDP)- too bad they don't offer the thermal coating catalogue wide.? What does Scat use in their rotators?

Re: 383 build spec help needed
 

I've never used their hyper-eutectic pistons so I can't comment on them. The only other pistons I have used are TRW Forged (many years ago) and SLP/JE pistons with great results. A garage my dad worked for used Ross Pistons for their antique race cars with great results as well. A friend of mine had his LS1 built into a 383 by Bischoff Engine Service and they used Ross pistons in his motor as well.

Re: 383 build spec help needed
 

On certain lines- LS and Hemi they have full coatings- don't know why they haven't fully implemented it yet.

Re: 383 build spec help needed
 

Just be mindful before any final bore/hone sizing,the pistons need to be in the hands of the machine shop.Even more so for pistons with coatings. Should look into what ring sets go with coated pistons as well.

Re: 383 build spec help needed
 

Too bad the learning curve was sooo expensive;(
I'm just choosing brand and type- the shop is well respected and it's in their hands really.

Re: 383 build spec help needed
 

Most are going to have a problem with this next statement.You don't take your bacon to a restaurant,so why don't you let the machine shop pick your parts based on your goals??.

Re: 383 build spec help needed
 

That's correct and to a point what has been done here as they have the years of experience and are constantly busy. Unfortunately instead of hands on I had to ship to another province as there are no shops here- makes me very uncomfortable as I like to at least see the shop and get some face time. Anyway i supplied some cam specs and we went over them to his satisfaction, his shop really caters to the speed crowd so I had to remind him of application, vehicle weight, octane used- so no 10.5:1 high compression just 9.81: max. He's using the Speed Pros because of application and they work for him. Tightened up the bearing clearances as he likes to run 20-50 oil, so standard vol high pressure pump. Just basically rechecking the machining and correcting. I wanted the Scat Por Comp 5.7in 7/16 rods- he doesn't as they clear the cam but he says the cylinder bottom have to be clearanced for 383- so he likes the regular Scat rod with clearanced bolt shoulders. Not to my taste but will trust him- 383 after all is old news and my app will not run over 6k. Saving the Mahles and existing balanced rotator for another 350 block with RHS vortec heads- just recycle most things. As far as the pistons go- lots of choice brand wise but between low end and mid level- huge gap in price.

Re: 383 build spec help needed
 

No problem here with that statement. Good example, a friend dropped off a block and a new Eagle rotating assembly to an engine builder. Once they got into the assembly all of the bearings had to be replaced with .001 bearings because the crank was ground a little too small from Eagle. If it was left up to the shop to get the parts they would measure the crank and then order the correct parts.

Just FYI after the .001 bearings were installed the clearances were from 0.0028 to 0.0031

Re: 383 build spec help needed
 

Are the extra cubes of a 383 over a 350 worth all that much to you? I found myself in the same situation not too long ago. Didn't want to deal with a hit and miss machine shop, so I wound up the getting the ZZ4 short block for my build. It's a block with a rotating assembly, that's it. You get nothing else. Crank, rods, piston, and block. The crank is forged just like the 383, rods are powder, and they use hyper pistons. If you're going to be re-using everything but that, which it sounds like you are if I read correctly, I don't think it's a bad choice. It doesn't come with unnecessary items like the 383, and it's significantly cheaper (almost half the price US dollars). I haven't fired mine up yet, but I have less reason to distrust a factory put together engine than Joe Schmo's crack at it.