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I feel like I'm near the limit of the current combo also. This is with a stock ls3 block, stock crank, stock main caps, and stock main fasteners. Just K1 rods and wiseco pistonds with ls9 gaskets, the cheaper arp head studs, and stock casting cathedral port heads over spinning the **** out of the F1a-94 head unit. Absolutely no heat issues with e85 and meth injection with the large air to air. With that in mind better flowing aftermarket casting heads, the higher end ARP head studs, and a stronger short block is all I need. Everything else about the current combo should be capable of getting me close with maybe only a bigger head unit needed. I know guys have made 1200 rwhp with an F1a-94 so I'd imagine my 241 heads and retrictive 2.5" dual exhaust is making my combo a little inefficient since my trap speed suggests I'm only near 1000 rwhp.
I've been running this short block for 5 years now it was built by TSP and I started with the D1x at 15 psi. The last couple years have been with the F1a-94. This long block owes me nothing at this point. LS7 lifters and ws6store rockers.
Outside of the short block I put it together and installed it as well as have done all the tuning since the beginning.
2.5in exhaust??? Jesus, you probably have 100hp right there at your level. If it's doing that good, build the LC9 and slap your whole topend on it and see how far you get. You need a dual 3.5in exh at a minimum for your power level. You can cam around a shitty exh, but it's not the same as getting it right.
Yep 1 3/4" primaries to 3" collectors with catless midpipes and magnaflow 2.5" dual exhaust. The catback and cai were the only performance mods on the car when I bought it. I liked how quiet and sleeperish the catback is so I kept it. It's definitely holding me back at this point.
I will definitely be getting better heads for the new combo, but I will not worry about what heads specifically until I have the short block plan nailed down.
Looks like Mast has a new cathedral port small bore head as cast coming soon that has 11-degree valve angle and uses ls3 rockers that works on the factory 5.3 bore.
If anything, wait for the BTR canted valve cathedrals. FYI, you need a 15 degree head because the ex port is better. The intake doesn't matter so much because if the boost, but the ex port does. IThe AFR 205 would be ideal, super fast intake, big ex port.
If anything, wait for the BTR canted valve cathedrals. FYI, you need a 15 degree head because the ex port is better. The intake doesn't matter so much because if the boost, but the ex port does. IThe AFR 205 would be ideal, super fast intake, big ex port.
I looked at the AFR heads but they don't work on a 3.800" bore:
The head options on a 5.3 bore are looking like a limiting factor on this combo. Those brodix only flow 180 cfm on the exhaust side stock 241's on the 5.7 flow over 200 cfm on the exhaust side. The LC9 with the L8T looks like a nice budget combo but there are some issues and one off parts needed. Crank snout diameter is different, heavy metal needed for balancing, 24t reluctor doesn't clear block with this crank so clearancing needed, piston options limited and may need custom pistons, and cylinder head options are limited even with expensive options flow isn't great.
I appreciate all the input. I will have to take some time to think about it.
The head options on a 5.3 bore are looking like a limiting factor on this combo. Those brodix only flow 180 cfm on the exhaust side stock 241's on the 5.7 flow over 200 cfm on the exhaust side. The LC9 with the L8T looks like a nice budget combo but there are some issues and one off parts needed. Crank snout diameter is different, heavy metal needed for balancing, 24t reluctor doesn't clear block with this crank so clearancing needed, piston options limited and may need custom pistons, and cylinder head options are limited even with expensive options flow isn't great.
I appreciate all the input. I will have to take some time to think about it.
You can't believe everything you read, the advertised flow numbers for the Brodix are unported. You can tweak the exh side on the port job and put a bigger valve in if you want too It's the best head on the market for a smal bore for a reason. All the big boost 5.3 block racers are using them right now.
Point being options are limited and with additional machine work, balancing, custom one off ports, and taking expensive heads that need additional work and it starts to not be as budget friendly as it originally appeared.
Going with a block with a bigger bore and off the shelf, crank, rods, and pistons makes it a lot more friendly for a small town guy like me doing my own work without any high end machine shops in town. Cost may be higher but getting everything together quicker with less hassle has value to me in my situation.
I feel like I'm near the limit of the current combo also. This is with a stock ls3 block, stock crank, stock main caps, and stock main fasteners. Just K1 rods and wiseco pistonds with ls9 gaskets, the cheaper arp head studs, and stock casting cathedral port heads over spinning the **** out of the F1a-94 head unit. Absolutely no heat issues with e85 and meth injection with the large air to air. With that in mind better flowing aftermarket casting heads, the higher end ARP head studs, and a stronger short block is all I need. Everything else about the current combo should be capable of getting me close with maybe only a bigger head unit needed. I know guys have made 1200 rwhp with an F1a-94 so I'd imagine my 241 heads and retrictive 2.5" dual exhaust is making my combo a little inefficient since my trap speed suggests I'm only near 1000 rwhp.
I've been running this short block for 5 years now it was built by TSP and I started with the D1x at 15 psi. The last couple years have been with the F1a-94. This long block owes me nothing at this point. LS7 lifters and ws6store rockers.
Outside of the short block I put it together and installed it as well as have done all the tuning since the beginning.
If your 241s are stock maybe have them ported while you find a better set of heads. I don't build engines; however I do port heads for friends so I'm going to share some pics to give you an idea of what ported 241s should look like. 241s ported should help your combo make better power under the curve. The exhaust valve guide is not completely done as I could touch it up a little bit more; anyway something like this would go a long way in making power.
At this point I'm not going to invest any more effort into making more power with the current long block. I will run it as is until I either hurt it or have the next motor ready to drop in. Currently I'm leaning towards a dart iron block, callies crank, boostline rods, and some aftermarket casting cathedral port heads. A short block like this could be built for around 12-13g and handle 1200+ rwhp easily.
I'm thinking 4.125 bore and stock stroke with forged callies crank. 388 cubic inches.
I looked at the AFR heads but they don't work on a 3.800" bore:
The AFR 205 heads will work on a 5.3L Despite what it says. The Exhaust side is the issue not the intake. Some guys have put a 2.02 valve on stock castings in that bore. Now a Flow Bench might be tell a different story as the valve MAY shroud in that bore. I don't own a flow bench I only know what some head porters have told me based on there testing. I have 2 inch valves in my 706 heads My Mamofied 205's have a 1.95 valve in the intake.
Furthermore, If you spend the money with Tony Mamo, He can put in whatever size Valve you want. I have a set of his 205 heads with 1.95 intake valves for a stock bore 5.3L These are not his bread and butter and does not really advertise them but he can and does build them. The motor has not been to the Dyno.
I will look for a picture I took of a 5.3L with a stock head that has a 2 inch intake valve in it.
Here is a stock bore, iron 5.3L with a junk 317 head on it. I zoomed in on the original image and took a screenshot so we can better see the valve placement. This pile is still sitting as a mock up in my race car.
I still think for a 3800 lbs race weight and my power goals an aftermarket block with more cubic inches is the way to go. The 5.3 combo being discussed is probably amazing for a lighter car with a turbo. I really like the 400" short block LME sells here:
400ci with the 3.750 stroke is another great option. Between it and a 388 I think you're splitting atoms as they are both big bore options and that would be just more of do you want to say you have 400 or 388ci. The selection for cranks with the 3.750 becomes a little bit narrower as well if you wanted something a bit stouter than the Compstar.
Looks like Mast has a new cathedral port small bore head as cast coming soon that has 11-degree valve angle and uses ls3 rockers that works on the factory 5.3 bore.
And their Black Friday sale had them at like $1000 off.
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