Thread: street/strip flat tappet 355
31-10-2015, 12:19 AM #1
street/strip flat tappet 355
another engine near completion in the shop at the moment is this 355 we are doing for a long time customer of ours
this engine was previously a std stroke 304 nothing fancy, cast pistons A9L rods, with a set of my 260cfm 1.94 valve VN heads with a crane 288 11:1 comp, TP single plane, 650 QFT, 1 3/4 tri Y's, good ignition etc, was in a VH street car and ran a best of 11.1 @ 121mph with 4.11 and 5k stall, unfortunately that car has been sold so we wont have a direct comparison to the old combo but this engine is going in another VH so providing the set up is similar to the old car producing 10 sec ET's is the goal
quick run down on the new 355 version, this will aslo be driven on the street and raced with pump fuel only, engine will be going on the dyno in the next couple of weeks
VR block, sonic tested, grout filled past the bottom of welch plugs, bored and TQ plate honed .040 over with our 4 bolt conversion using CRD steel center 3 main caps with 7/16 outer cap screws, de burred etc
basic oil mods including blocked #4 lifter gallery feed with cross over behind #1 cam bearing, external oil pickup conversion, modded oil pump and sump with -10 drain backs from rear of cyl heads
scat 355 9000 series crankshaft
scat 6" 7/16 bolt I beam rods
CP bullet pistons
VN heads with my latest mid size port design CNC cut then hand finished, ferrea 2.050/1.600 6000 series intake and exhaust valves, crane springs retainers and locks etc, flows around 290cfm, milled for 11.3:1 CR
TP single plane off the std stroke engine, port matched with plennum mods
750 cfm pro systems carb
custom grind solid flat tappet camshaft nitrided, edge orifice lifters
YT platinum roller rockers.
some pics of the build so far
31-10-2015, 12:20 AM #2
31-10-2015, 06:13 AM #3
Definitely Subscribing to this one! Might try to copy some stuff onto my spare VR block.
I'm guessing that there was no clearancing required extra to the factory cast in clearance's?
31-10-2015, 06:59 AM #4
Nice Pete. What size sft you going or is this another squirrel grind lol
31-10-2015, 08:23 AM #5
10's will be a walk in the park mate , it's looks another quality build !firstname.lastname@example.org on e85
31-10-2015, 08:43 AM #6
- Join Date
- Jan 2009
- In the shed
Nice build. I like the ft but why no roller either hyd or solid? Cost?
31-10-2015, 02:02 PM #7
- Join Date
- Feb 2011
Some more Hpe power to hit the track,good job
01-11-2015, 12:52 AM #8
doing a HYD roller to suit this application that will see 7000+ rpm and remain stable can get expensive due to the cost of using premium quality lifters and keeping the valve train light, the 372 we did had no probs turning 7200 rpm but it has good quality crane lifters and light weight valve train components all of which cost top dollar so cost would be a major factor doing a hyd roller for this application
id really only rate the cheaper HYD lifters with smaller wheel and cheaper valving to around 6500 rpm with conventional parts
01-11-2015, 01:13 AM #9
01-11-2015, 01:15 AM #10
01-11-2015, 03:23 PM #11
Sounds good mate. Be interested to see the power output of these....
01-11-2015, 06:44 PM #12
- Join Date
- Jan 2012
Thats a good looking build!!
whats the theory behind choosing a custom ground cam?
Noticed the pistons have valve reliefs... How are you getting the comp up to 11.3 with them?
01-11-2015, 09:01 PM #13
basically we can choose the lobes we want to use rather than be limited to whats available with shelf grinds, nothing wrong with a shelf grind but i wanted something specific that suits these heads and the overall combination and other parameters like lift, lobe sep, specific exh lobe etc
55.5cc chamber and 6.8cc valve relief, chev piston was chosen to suit the chamber volume as these heads were already milled, also the block had been previously milled for zero deck with the std stroke combo so the pistons are now +.020 above the deck, rather than machine the crown on these pistons down further which brings the ring land closer to the top of the piston weakening the ring land we will be using a .060 thick cometic which will still give us a piston to head clearance of .040
02-11-2015, 10:34 PM #14
03-11-2015, 09:18 AM #15
- Join Date
- Jul 2007
This is real close to a 355 I'm just finishing up - virtually identical rotator except we're using CP's with no valve reliefs. I'm a fan of the Scat Procomp I beams, nice compact big end on them, fairly light & plenty tough.
We're just using 2 bolt mains with 1/2" studs.
We went for a SFT for the same reason - going to need to spin past 7000 & will get street driven quite a lot, going past 7000 means a hyd roller is pretty much out, regular street driving & ability to do quite a few kays between maintenence means a solid roller is out, leaving a SFT as the best option if the budget is not there for $$$$ parts.
The rest of it is VT heads flowing 28x/19x, 2.055 & 1.625" valves, 11.7:1 comp, harrop intake, QF 850 carb, 264/268 on 108 custom SFT cam sporting .635" lift after lash (.380" intake lobe, 1.72 ratio rockers).I'm not on here much any more - don't bother PM'ing me, chances are I won't read it, just call me on 08 8376 9540 if you need to get hold of me or email email@example.com, phone is better!
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