1991sleeper

iTrader: (-3)

Sweetness I didn't think a 305 would run these kind of times in TBI form with factory parts .. I'm in the process of building my LO3
NOW! ... Here's what it's gonna be .. Stock bottom end LO3 .30 over 9.6-10:1 CR , LO3 heads milled .10 and ported by myself w/1.94 valves Mabey 1.55ex. , summit stage 1or2 intake (idk yet) , MSD billet ESC distributor , Howard's HR cam .488IN 264dur .495ex 270dur 114 LC 110 IC/L ( intake open -3 closes @ 37 exhaust open @ 47 closes @ -9 TDC overlap -12 .. Shorty headers into 2.5 Y & full 3" exhaust W/ 3" cutout right in front of rear axle .. Hv/HP oil pump and thinking about a rev kit .. Oh and I also have roller 1.6 rockers .. So that makes the cam like 512&524 I think ... How do u guys think this thing will run ? I also thought about make I a 334 lol just to be different .. And so I can smoke some new mustangs/ camaros lol

Edit : oh yea I have CFM tech's 620 CFM 5.7L TB .. What size injectors should I go with ? I also have an aero motive VRFPR with the factory regulator blocked off
And I have 4.10's with T-5 and LOTS of suspension upgrades ! I wanna run atleast 8.00's in 1/8 th

Fast355

iTrader: (2)

I wouldn't make it a 334, JMO...If you are going to stay 305, build it cheap, otherwise step up to a 350. If you build the 305, rather than building a cheap 334 stroker spend the money to build the 305 right. That is balanced rotating assembly, align bored, deck plate honed, preferably with poor mans 6" rods, good oil control, and gapless rings.

I built a poor mans 6" rod 305 not long ago. Pistons for a 6" rod 305 are off the shelf items. A "Baby LT1" 265 has a 5.94" powdered metal rod in it. Use those rods with a 1.26" compression height 305 piston (rather than the typical 1.54" rebuilder job) and mill the deck until the piston sits .010" in the hole (I believe we took .040" off the deck). Then run a .028" compressed head gasket. Long rod motors LOVE TO REV.

Your LSA is too wide for a 305 IMO.

1991sleeper

iTrader: (-3)

Y is the LSA to wide ? I thought we wanted 114 w/ EFI for tunning reasons ? Idk much about cams ??? Also how will it sound with this cam ? Good lopey idle ?

1991sleeper

iTrader: (-3)

I'm trying to keep this build under 2k $ :-/

Fast355

iTrader: (2)

LSA is too wide, because the tighter LSA helps move air through the restricted ports and bores of the 305. Swirl port heads also run the best with single pattern or straight pattern cams or cams that are very close to straight pattern. The swirl ports also favor tighter than normal LSA because they help shift the power curve lower.

114* is what you want for a close to stock replacement. A novice tuner might have better luck with a wider LSA, but someone like me that wants power, tighter is better. A 305 with 1.94/1.60 valves appreciates a 109-110* LSA on a 215* @ .050 cam. Factory 305 cams are 109* LSA.

The cam you mention will have a relatively smooth idle on a 114* LSA. It would sound about like a Hotcam on a 112* LSA and sound about like my brothers Vette on a 110*.

Fast355

iTrader: (2)

My myself and I....Low budget 305 build....


Factory Roller 305 block
L31 Vortec heads with 1.94/1.60 valves and exhasut ports cleaned up with full LT4 springs, retainers, and keepers.
Block bored .030" over, align bored, deck honed
5.94" rods, resized with ARP bolts, hooked to a 1.26" compression height piston......EDIT---I will finish the deck height/compression math in the AM...Its looking all weird....Correction the engine I built had to have been decked .055" based off the math I just performed but this will vary depending on the specific engine and components. We left the piston .010" in the hole and ran a .028" compressed 350 head gasket for 10.15:1 compression. Don't worry about the high static compression ration, the dynamic compression ratio with the below cam is only 8.31 with roughly 170 psi cranking compression. Generally 8:1 dynamic compression ratio is the number to shoot for, but with Vortec heads, a knock sensor, and good quench 8.3:1 can be pulled off easily.
Custom Roller cam using XE 270 lobes.....270/270 @ .006, 218/218 @ .050, .495/.495" lift, 110* LSA, 4* advanced on a 106* ICL
Edelbrock 2912 Single Plane intake with 620 CFM bored TBI, using 61# injectors @ 30 PSI tuned with the EBL setup.
1 5/8" primary headers are way too small for this build, I would look into some DynoDon's 1 3/4" primary headers and run a good 2.5-3" merge Y with a straight through muffler design.

I think it could make 400 HP @ 6,000 and 390 TQ @ 4,500. I think it would make over 350 ft/lbs of torque by 3,000 rpm.

1991sleeper

iTrader: (-3)

So ur pretty much sayin the combo I listed ain't worth a **** lol I'd b happy with 325-350hp is this possible with ported and polished swirl ports ? I'm about to be laid off n will have all the time in the world to shine them ports up nice n perty like however I won't have a bunch $ for rods pistons n a bunch of machine wrk :-/ I was hoping to get my 8.00 1/8 out of what I got n not have to go into a bunch of detail with machine wrk and calculating rodn n all that cause I have no idea about all that stuff really .. Don't get me wrong I have built a couple engines before but idk about rod length combos etc . But I do consider myself a fast learner and am willing to learn anything someone is willing to teach ! Thanks ppl !

seanof30306

iTrader: (4)

Fast, can you source that data?

Fast355

iTrader: (2)

On a flowbench with a 454 TBI. The TB was flowed dry but keep in mind that at WOT you are pushing though ~12.5 × more air than fuel by weight so fuel flow results in a minimal loss of airflow.

seanof30306

iTrader: (4)

You did that yourself?

Big Dog Chevy

Finally someone who understands building motors!! It's so funny how people are so quick to say it can't be done instead of show me how to do it.
Now that cars converter was loose but to gain a little more MPH up top I tuned it to lock up right after the 3rd gear shift. Testing back then showed a 1-2 mph increase. That car also hooks pretty good (26" MTs) so wheel spin is not an issue. It also has a custom 2.5" true dual exhaust that I built and has two Magnaflow straight thru mufflers which let's the motor really breathe and really helps the top end charge. It also has full synthetic fluids and a lot of small things that add up. That car has more in it cause it drives and sounds so mild so if he went with more cam better heads and a little more CR with a re-tune i think he can bang 11s easy and still be very streetable. It's funny cause he has beaten some cars that on paper he should have lost to lol.

Big Dog Chevy

A 2.5" Y pipe will Kill a lot of power! You have to put a much better exhaust system on that thing. You have to remember how inportant a good exhaust system really is on a motor.

Big Dog Chevy

It will make that with no problem. If you have a flow bench and can port your own stuff do a full port job on those heads. I have gotten Vortecs to flow some crazy CFM for what they are over the years.

Fast355

iTrader: (2)

One can get a crazy CFM for the intake port size from either 305 or 350 Vortec heads. Even the 059 casting 305 heads do quite well in stock form for a 305. They have very good burn rates and it is possible to make good power, from a higher than usual compression ratio as long as the quench is right and you keep the engine cool....170*F thermostat is what I run in everything OBDII or not.

I have had access to a couple of flow benchs over the years.

Fast355

iTrader: (2)

Not if he runs a properly setup merge Y to 3.5".

Big Dog Chevy

True, a few years ago I did a dual 2.5" off the headers into a single 4" that had a total length of 56" (terminator box) back into dual 2.5s going into two pypes 6" round mufflers. Ran a sample port at the 4" and at WOT it showed like 1.5 psi on the test from a 400rwhp car.

1991sleeper

iTrader: (-3)

I have 1 5/8" primaries 2.5" collector w/ custom 2.5" pipes that run into a flowmaster 2.5 in 3" out Y transition with a 3" cutout in front of rearend and 3" all the way to a 3" flowmaster single in dual out with 2.5" tailpipes and 3 " rolled stainless tips ... Any more suggestion on my LO 3 build ? I think I'm goin with a summit stage 1 intake idle-6000 rpm and ill clean it up and port match everything on the way in & out

Ill prolly have a track tune for uncapped and a street tune for capped cause I hear these cross flow mufflers don't flow too good

Big Dog Chevy

Yeah if you want the most hp/trq sell that flowmasters 3" stuff and run a minimum 3.5" with dual straight thru mufflers behind the wheels. I have done many systems like that for 3rd and 4th Gens and they always show a big improvement when you open them up IMO. If not then you are leaving power on the table.