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This is all the info I put in another thread under engine swap. I thought I'd copy paste it here where I might get responses about what you think my hp/tq and a guesstimated et might be. Happy bench racing.
Originally Posted by BeyondZ28_85
Hi all. My son was recently born so I've taken some time away from my project. Now I'm anxious to dig back into it and thought I might share some info and a video about my car. I've got a 2 bolt main sbc 400 punched .040" over to a 408 (closer to a 409 but don't want it confused for a W motor.). Heads are an old smogger set that have 76cc chambers, good porting, 2.02"/1.60" undercut swirl polished stainless steel race valves, 1.6 Howards roller rockers and springs to match my Howards hydraulic roller .560/.560 (.597/.597 with my 1.6 rockers part # CL111815-10.) Pistons are forged aluminum flat tops with deep valve reliefs on 5.565 I beam rods taking me to a pump gas friendly(ish) 10.0:1 compression ratio. Torker II and Holley 600 cfm (I know way too little carb this is just the intake and carb I had around when I was eager for the first fire. The 750 had some gaskets tear while setting float levels.) fuel is supplied by a Holley black pump with the supplied regulator from the summit kit. Torque converter is somewhere in the vicinity of a 3200 stall in my car. I have a Mellings high pressure oil pump. Cooling is handled by a Be Cool direct fit system with dual puller fans. This is all fed through a TH350 and what I think is the stock rear end. I foresee my trans and rear end being replaced soon with this kind of abuse. The trans plan is a TH400 full manual reverse valve body in the future. I'm not sure what gears are in the car. I'm hoping that my Z28 came with the 3.23 posi. I plan to figure that out when I can take the car out for a cruise. Certainly better than the slightly hopped up 305 that came in the car with only 1 side actually having the bolt through the motor mounts. So any of you experienced gentlemen have anticipated power output/ 1/4 mile ets for this car. I don't have good rubber on the car so if you want to estimate ET based on the right rear end and a good set of slicks feel free! I know I've got a ways to go before this car is finished. Recommendations for improvements are very welcome while insults are not. I'm still and forever will be a student in all this. When you stop learning, you stop progressing. Here's a video of myself and Dad during the first fire. Keep in mind that timing hasn't been tuned in and the car was kind of thrown together in a way we could see and moniter everything.
Depends on what good porting is lol i'd say 425 hp or so, given small intake and carb. Would be better with an air gap type performer rpm and 750
Valve is small for a 4.165 bore so i'm guessing heads dont flow much more than vortecs
I've not heard of 2.02"/1.60" valves being small. I'll have to put it on a dyno at some point to find out for certain what power I'm seeing. How do you think a weiand tunnel ram with dual Holley 450s would do on this combo? I'll definitely agree there are better heads, but I think my stainless steel undercut and swirl polished valves would fit right in a set of awesome aftermarket heads.
As is I would say it would run high 13s. With better gears, intake and carb, heads.. it could turn in the 11s. 400 sbc are beasts! My dad had a 406 in a 67 Chevelle SS that ran 11.30s and he drove it to the track as well as shows. It had a roller cam similar to yours and Brodix heads.
Orr's being generous. You don't mention exhaust. You're at 375 rwhp TOPS.
1 3/4" primary full length headers with plans for X-pipe and dual exhaust through mufflers. May uncap them at the track to see if it cuts any time off my 1/4 mile time. When I replace headers, I want to find 1 7/8" primary long tube headers. Not in the budget for now though.
So here is a list of the parts I plan to get to finish off my build. Alternator, locker, wheels, and tires first. Then shifter and possibly valve body depending on how mine acts. My current valve body doesn't require vacuum modulator, kickdown linkage, and holds gear until I shift so I think the shifter is really what I need. Then gauges. Finally, I'll step up to better heads and intake. I did get my 770 Holley competition carb fixed. Anyone want to weigh in with what they think or if what I've selected will work?
Edit: could not use link
Plan to mount one size on 15x8 and other on 15x10.
I think this locker will bring down my 60' times while still allowing me to turn.
Don't think I'll need the valve body, but I found one just in case.
Last edited by BeyondZ28_85; 03-16-2016 at 03:47 AM.
So that's just over $2500 for wheels and tires, high amp alt for my be cool fans and other accessories, and a locking diff. I'm going to guess its going to leave hard and fly.
Probably 350hp, maybe 375hp with those heads, which are going to hold you back more than anything.
Don't forget that many lose 25, 50, or even 100hp by not having the right exhaust and incorrect tuning (ignition curve, carb, and even the intake tract)- it is extremely important...
Probably 350hp, maybe 375hp with those heads, which are going to hold you back more than anything.
Don't forget that many lose 25, 50, or even 100hp by not having the right exhaust and incorrect tuning (ignition curve, carb, and even the intake tract)- it is extremely important...
Yeah but 1000 ft/lb to one wheel won't be as fast as 500 ft/lb to both tires. I agree there's more power to be extracted from aftermarket heads and an intake (see Dart Iron Eagle and Weiand Team G); however, I can use the power I have now to start setting up the suspension, chassis, and rear end. By doing so, I think it'll be easier to dial in the suspension when I do go with aftermarket heads and intake. This car will also be fun to drive on the street with the limited slip locker that allows the tires to spin at different speeds until one breaks traction...more like a riot. I might do a transbrake TH400 later, but for now I think a built TH350 will do just fine and probably perform better as long as it holds gear and shifts hard. With something around a 3.42-3.73 gear it should do ok as a crossover and then perform much better with the new heads and intake. Maybe a Dart 427 short block later on. My motor is already ahead of the rest of the car so I think it's time for a little catch-up. I've also contemplated a fiberglass front clip to even out weight distribution. The genius who had the car before me butchered the original front clip so he could fit a "Cadillac Escalade" front grill into the lower fascia so I'm looking to fix the nasty cut hole anyway. I might just cut and sculpt the opening a little to repair it. Better cooling that way anyway with the enlarged hole...but that lighter front clip would certainly take weight off the front of the car.
Yes you do need the right trans and rear, but a 10 bolt is not going to last very long with a 408 under the hood. Too many people upgrade for a lot of money, nuke the rear and still have to go aftermarket anyway. That would be doing things 2x for no good reason. Of course an upgraded trans is always a good idea, as is suspension.
Don't get caught up in weight distribution so much for a street car - suspension is much more important. You can move the battery to the trunk for a few $ and it will help even more than a fiberglass front clip. A fiberglass hood and aluminum heads is an easy 100lb reduction up front.
Originally Posted by BeyondZ28_85
Yeah but 1000 ft/lb to one wheel won't be as fast as 500 ft/lb to both tires. I agree there's more power to be extracted from aftermarket heads and an intake (see Dart Iron Eagle and Weiand Team G); however, I can use the power I have now to start setting up the suspension, chassis, and rear end. By doing so, I think it'll be easier to dial in the suspension when I do go with aftermarket heads and intake. This car will also be fun to drive on the street with the limited slip locker that allows the tires to spin at different speeds until one breaks traction...more like a riot. I might do a transbrake TH400 later, but for now I think a built TH350 will do just fine and probably perform better as long as it holds gear and shifts hard. With something around a 3.42-3.73 gear it should do ok as a crossover and then perform much better with the new heads and intake. Maybe a Dart 427 short block later on. My motor is already ahead of the rest of the car so I think it's time for a little catch-up. I've also contemplated a fiberglass front clip to even out weight distribution. The genius who had the car before me butchered the original front clip so he could fit a "Cadillac Escalade" front grill into the lower fascia so I'm looking to fix the nasty cut hole anyway. I might just cut and sculpt the opening a little to repair it. Better cooling that way anyway with the enlarged hole...but that lighter front clip would certainly take weight off the front of the car.
Also the 770 CFM Holley Competition carb, I am tuning it to my application. It's also a vacuum advance unit to simplify it. The boosters will be tuned as well. This will be an extremely tuned carb that offers greater throttle response even in low vacuum situations. This is without having any vacuums hooked up so the carb receives the greatest signal possible. I'll be able to retune it at every stage of the build. All ports are gasket matched to maximize flow with 5-angle 2.02 Intake and fully radiused 1.60 exhaust. That's before I step up to 230cfm intake runners with 2.08 intake and 1.60 exhaust that also get ported and polished. Those ported Iron Eagle heads will flow really nicely with a Weiand Team G intake swirl ported to them. All that with a .600" hydraulic roller cam (with 1.6 Howards Purple Full Roller Rockers) with dual pattern favoring the exhaust a little and in a little milder duration. My vacuum secondary carb with tuned boosters will run stoich through the rev range at any throttle position. Especially when I actually get some 1 7/8" primary tuned length headers through 3 1/2" dual exhaust. Maybe brought out to the sides behind the doors. Then stepping up to a Dart 427 short block with forged internals. I think it'll end up being like a rat guised in mouse cloak so it is actually still lighter up front and handles to its max potential while also launching. I'm already +CID over a 396 BBC without the weight penalty.
Last edited by BeyondZ28_85; 03-16-2016 at 08:05 PM.
I also have a thread over in LSX swap for a carbed LSX 454 build. I'm trying to get most of the car in place so all I have to do is drop that motor in. It's a dual quad tunnel ram motor that I want to build. I'm actually going to build my car around being able to do it. Can an 85 Z28 beat a 2015 Z28? Power to weight? More power less weight. EFI vs tuned dual carbs with mechanical secondaries and MSD? Sure I'll nod my head your way there slightly. Tunnel ram cold air intake vs stock box? I think my tunnel ram looks a little cooler and is way more functional. Suspension on my 85 upgraded and running on new Z28 wheels and tires. Limited slip locking differential. I think it'll compete. I just might build a Vette cart on the side as well.
I love building 400smallblocks...I agree with the others,,350-375hp tops...Take those heads intake and carb and throw em in the river,,,replace em with anything aftermarket with at least a 200cc intake port a modern air gap manifold,,and the best largest tube headers you can afford...That'll put you over 450hp easily,,,next one you build run a longer rod in it also
Yes you do need the right trans and rear, but a 10 bolt is not going to last very long with a 408 under the hood. Too many people upgrade for a lot of money, nuke the rear and still have to go aftermarket anyway. That would be doing things 2x for no good reason. Of course an upgraded trans is always a good idea, as is suspension.
Don't get caught up in weight distribution so much for a street car - suspension is much more important. You can move the battery to the trunk for a few $ and it will help even more than a fiberglass front clip. A fiberglass hood and aluminum heads is an easy 100lb reduction up front.
I wasted 2 10bolts with a 305,,my little brothers S10 with a 408s on his 3rd rear-end
01-26-2016, 04:01 PM
