400FWHP TBI build attempt thread

[Gojira94]

Block is a stock deck, 2005ish GM 1-ton Vortec 350 crate engine. Hecho en Mexico. Where are you calculating your quench from? The top of the piston recess? My pistons are 0.025" down. The GM ZZ4 and 330 HP 350 HO ran 0.051" compressed head gaskets when they were built. The ZZ4 had flat tops and L98 aluminum heads and the 330 hp 12cc dished with Vortecs. I feel the slight compression difference advertised between the factory Vortec engine and the 330 HP crate is due to the head gasket.

I'm using the rudimentary method for calculating quench. Volume of cylinder from top of piston to deck height (.025) + compressed gasket thickness (.026) = .051"

My SCR I used the calculator at CSG's site (http://www.csgnetwork.com/compcalc.html) and DCR with the calculator at Wallace Racing's site (http://www.wallaceracing.com/dynamic-cr.php). I'm calculating at 340' altitude for mine, just above the sandhills region of NC. I asked about intake valve closing after BDC to get a ballpark of how much DCR you'd be running. You have more than I thought you might. A lot of folks I've heard say above 7.8-8.0 you'll want to run gas with an octane rating higher than 87 vs. detonation. Being that almost all 87 octane fuels have 10% ethanol it actually pads that ever so slightly. How much would be pure speculation. But I'm accounting for the difference in stoich for ethanol blended fuels in my EBL/TunerPro stuff.

[Fast355]

I'm using the rudimentary method for calculating quench. Volume of cylinder from top of piston to deck height (.025) + compressed gasket thickness (.026) = .051"

My SCR I used the calculator at CSG's site (http://www.csgnetwork.com/compcalc.html) and DCR with the calculator at Wallace Racing's site (http://www.wallaceracing.com/dynamic-cr.php). I'm calculating at 340' altitude for mine, just above the sandhills region of NC. I asked about intake valve closing after BDC to get a ballpark of how much DCR you'd be running. You have more than I thought you might. A lot of folks I've heard say above 7.8-8.0 you'll want to run gas with an octane rating higher than 87 vs. detonation. Being that almost all 87 octane fuels have 10% ethanol it actually pads that ever so slightly. How much would be pure speculation. But I'm accounting for the difference in stoich for ethanol blended fuels in my EBL/TunerPro stuff.

I have never run this engine on 87. Even STOCK on the stock tuning it had knock retard on 87 octane. The GM 395 Marine cam made it worse at 9.6 static. It was about 8.4:1 dynamic. I have had this engine drinking E85 with a flex fuel operating system for some time. With the old setup it had to have a very conservative timing map on 93. After E85 I was able to give it a healthy timing bump and gained power everywhere. With this setup I will be happy if I can run a good timing advance curve on 93. I also have a cooling system that never runs more than about 190°F on the hotest day.

[Gojira94]

It's been a little slow getting through the new short block. Every fastener and component being re-used has to be cleaned and some of it painted. Right now I've got the bottom end buttoned up, cam installed, timing set and cover on. First I painted the block (boring black) I repainted the oil pan, timing cover and will be painting the brackets on the manifold (also boring black). Water pump is almost new and fine. I still have some Old Ford Blue, thought that would look decent on an expendable part like the water pump. The aluminum accessory brackets need a good cleaning before they go back on.

The short block was advertised as being stock deck height/ .025 in the hole but eyeball evidence suggests otherwise. The china walls are still smooth but the pistons look a lot closer than .025 to the deck. Also, there are telltale machining marks on the deck. I went to some degree of trouble to acquire the Mahle 5746 .026" Nitroseal gaskets and I may not be able to use them. In some ways it may be a good thing, I may be able to shave a little off the compression ratio and tighten the quench at the same time. Anyway, here's a few pics. First one is the old short block (10054727 casting with 14088535 cast crank). Others are the new one.

[Gojira94]

This block has definitely been decked. Pistons in the hole:
1 .013
3 .015
5 .017
7 .017
2 .012
4 .014
6 .015
8 .017

I'd just call it a .015" deck height block. .008"-.013" below factory .025" deck height. With the Mahle 5746 gasket quench would go from .051" to between .038"-.043" which would be closer to ideal. Static CR would bump slightly and I'll have to go back to the calculators on that but I think SCR would be around 10.2:1. If this short block was the other offering with -12.3cc dish pistons I'd be shitting in high cotton on CR vs 87 pump gas in the mid-9s. I'll play around with the head gasket numbers in the .033"-.035" range and see if I find a happier medium. But if I'm above 8.1:1 DCR/ 9.7:1 SCR I don't think I'll be looking much different.

[Gojira94]

I carefully taped off the RMB seal housing and painted the back of the block, got the water jackets and all bolt holes on the deck cleaned out of the crate oil/ preservative and got the heads on. One word about the heads- for a $900 pair of heads I figured there might be one or two issues that come up. The holes for the dowels on the deck were slightly off or too small. They may have missed the finish work on those. Both sides I had to ever so gently open the holes up with a 5/16" drill bit, but after that they settled right down. My other concerns will be with the pushrod clearance and alignment to the casting. I can handle both. These heads have gotten high praise from Skip White and veteran porter Tony Sizemore at HeadBytes. Say what you will about Tony, but he did a video series of the 200cc head where ProMaxx gave him bare castings to cut up and analyze when AFR, TrickFlow, etc wouldn't do it.

I still have a number of things on the list to get it finished and buttoned up, including but far from limited to:
Finish cleaning and painting external parts like pulley, engine mount brackets, water pump, topside brackets
Clean front accessory brackets
Prep and install lifters, retainers & spider
Install intake, 180* thermostat, water neck
Figure out brake booster plumbing fitting size
Figure out heater to intake hose plumbing
Flush Radiator
Flush heater core
Clean oil cooler lines/ fittings
Install oil cooler block to engine block
Clean PS pump and double check for leaks

But anyway, here's some pics. Today I'll be digging out the tuning work I started in January 2017 and start getting feedback and help with that. Again, this is going to be EBL Flash driven with VRFPR. Wish I had a week off from work to just dive in and get it all done uninterrupted. :)

[Gojira94]

Rather old first attempt at building and smoothing a VE table, based on... gut I guess. No idea if I'm even close but this is what I started with, dreaming back in Dec. 2016. screen shots of both graphs as well. For spark tables I considered working with Vortec head stock tables as a fairly conservative ballpark, maybe even stock aluminum head LTI F body tables and dialing it back pretty broadly since classic Gen I SBC isn't reverse cooled. No chance of making 46* anywhere like an LT1, especially at 10.2:1 lol. This is where I really have no idea to build a spark table. I still think the Vortec tables are decent place to start, maybe something like an aluminum headed L98 as a base? The ProMaxx 2169 heads' flow numbers are well published, they post them on their site, Skip White measured them a year ago, I think HotRod magazine online had a budget head shootout with flow numbers when they were still Patriot heads, though I'm pretty sure that was a previous design.

[Gojira94]

Haven’t touched it for 12 days until tonight, very brief time spent. Cleaned up the spider I acquired from a boneyard LT1 D body. Also soaked the new lifters in virgin mineral spirits for an hour to clean them. Blew them dry with air and put them in the oil bath until tomorrow evening.

What I have been able to do is study the hell out of VE and spark tables from a variety of engines similar to what I’m putting together. I’m most familiar with F body LT1s. With a 218/224 - .528/.535 cam in 185cc aluminum heads I’m not too far away from an LT4’s flow characteristics. I’m a tiny bit bigger on cam, tiny bit smaller on heads (heard LT4s were 190cc heads, maybe not accurate). My goal is to put together a better 2nd attempt on the VE tables and take a stab at the spark tables in the bin and upload that in a couple of days. Scrutiny of more experienced guys would be welcomed.