305 0r 350 heads

[bignate]

whats up fellas well i got my motor in my truck and now i have to take it out and change my oil pan and decided to paint it while it was out.

i am taking night classes too get my ASE cert.

and i was talking to my instructor and he has a s10 v8 also he has a 350block 305headson it. hes runnin 8.10's in th 1/8 mile and can prove to me hes gettin 19MPG on his setup

700r4 tranny and a 3.73 s10 rear

he been a chevy tech for twenty years and is tryin to get me to run with a set 305 HO heads

says i can run 89octane street gas no pings

or problems i got the motor out and cant decide let me know what yuall think

[Bakas]

stay away from that idea, I had 305 heads on my old 355, thing was a dog after 4500 rpm, and you cant step up the cam because they wont flow. Go with the iron vortecs, hands down best bang for ya buck, need I say more??

[bignate]

right now i have the original 71 vette'

heads im told they are the old LT1 style i am also running a lunati .504 dur. cam with

2200-6500 op range. i have seen my instructors truck run and he aint got no problems with a .454 cam stock intake and rochester carb. like i said low 8's http://www.s10v8.com/images/smilies/icon_eek.gif

[riotpolice75]

ill let you know how the 305 HO heads flow on a 350 pretty soon. Thats the setup im running with. I ported mine so they should flow alot better than the stock units. thats a good thing hearing that he can run 89 in it. i had all but reserved myself to running premium in it







smith

[rudedogg]

all 305 heads are good for is to raise your compression! the gain is not worth the loss of flow..

[gdmclnh]

The 305 HO heads will flow better than stock 305 heads. But, I think you have too much cam and the cam has too high an operating range for 305 heads. A 305 with a towing or torque type cam can be very strong up to about 4800 RPM, give or take a little RPM. After that it falls off very quickly.

[redneckgames]

I agree, I ran a set of 305 heads on a 350 and was not happy with it. It had good low end, but stopped making power early. I'll never do it again.

[spacecadet]

On 2008-04-09 15:26, gdmclnh wrote:

The 305 HO heads will flow better than stock 305 heads. But, I think you have too much cam and the cam has too high an operating range for 305 heads. A 305 with a towing or torque type cam can be very strong up to about 4800 RPM, give or take a little RPM. After that it falls off very quickly.





I 2nd that opionion. I put a set of 601 305 heads on my full size k20. It was used to pull the race car trailer and haul firewood. It had alot more power with them on it compared to the cracked 624's that came off. I never twisted that motor over 4k. since I didn't need to so I can't tell you how it ran over 4k rpms. There is a good right up on porting the 305 heads and makeing them decent high flowing heads. I'll have to look and find the link for you. I think it was a 3M link to sell the kit.

Space

[riotpolice75]

305 HO head flow numbers (http://www.thirdgen.org/techboard/tech-general-engine/258259-305-cylinder-14014416-airflow.html?highlight=416+heads+flow)



Theres volumes of information on that sire about porting and heads in general. Well worth spending a few hours on there snooping.







smith

[Lin]

Don't do it! I have that setup and it sucks. 89 305 HO heads on a 69 350 block with flat top pistons. Bad Bad, goes flat at 5500 rpm. but you can't blow it up. You sure can smoke the tires. but very bad flow. I would not do it again.

[stroker1]

305 heads are OK for a street driven only low performance daily driver IF you use dish pistons. Other than that, STAY AWAY FROM THEM!!! And what about low 8s? That's not hard to do! http://www.s10v8.com/images/smilies/icon_eek.gif



If you have a '71 LT1 then you probably have #487 castings. They are not that great. But they flow much better than a 305HO head. They just lack the small chambers. If you need to increase your compression, just angle mill the heads or switch to a thin metal head gasket and spray it with copper coat. If you keep it around 10 or 10.5 to 1 with the 487 heads they will do fine. Oh, yeah. The 700R4 your instructor is using has a really low 1st gear and it's helping the 3.73 gears work coming out of the hole. And he obviously doesn't have to turn it hard because the 305 heads just will not rev on a 350. He is relying on torque to get it down the track.



To each his own! But I've had a 350w/305 heads in a 84 Monte Carlo. It was a dog. And spark knocked in the summer like a *****.



http://www.s10v8.com/images/smilies/icon_mad.gif

[355V8S10Tahoe]

I agree with stroker and most of the other members cutting down the 305 heads but I like to run emissions design 305 heads on my 355 with 1.94 intakes, pocket ported, gasket matched, flat top KB pistons, 272/284 adv. dur. 454/480 lift Crane Hydraulic, Performer RPM intake, 600 Performer carb and no spark knock on regular 87 octane pump gas, it's just a street machine though, never sees 5 grand much but has no problem getting there... http://www.s10v8.com/images/smilies/icon_cool.gif

And if your wondering, yes it's a 700R4...