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Discussion in 'Engine Topic' started by Riley, Mar 13, 2021.
Is there any summit heads, dart, or edelbrock someone would recommend?
I have jegs 290cc big block heads on my car. If their sbc heads are anything like those, I would highly recommend them. They make as much power as my friends AFR305 heads.
They have a jegs 180cc which would be perfect.https://www.jegs.com/i/JEGS/555/514002/10002/-1
yup, and even AFR has a budget-targeted Enforcer series at just under $1000 USD/pair.
fwiw, enforcer castings are Chinese.
I used these and they worked out quite well. Castings are heavy, made for Summit by Dart,
fwiw 5.3 and 5.7 are Also known as Vortec but they're Also in the LS series and, of course, LS heads do not fit a sbc or vice versa.
that 5.3 is a clue it's LS while 5.7 could be either sbc or LS.
Suggest learn casting numbers of GM heads you seek and put it in your search toolbox.
The compression question is a complicated one, and the real answer is multi-faceted with cylinder pressures related to the valve opening and closing events (good info here). HOWEVER for these purposes, we are discussing "static compression". With a flat-top piston, and 64cc combustion chamber compression will be around 9.7-1 (depending on deck height)
The short answer with how-much compression is, as much as possible without causing pre-ignition. With a carbureted iron-headed smallblock on pump gas, that is generally under 10-1
For heads I'm a huge fan of the Edelbrock E-Tec line. They use a similar chamber to the L31 Vortec head but are aluminum with larger ports. The 60989 is perfect here, you'll need 2
If you need to go more budget The L31 Vortec head is outstanding although much heavier in cast iron with less overall potential.
That's a very common issue when one goes down the "internet rabbit hole" trying to pick a 23* SBC cylinder head. Everybody gauges if a head is good based on material and "flow CFM" and not to say that's not important, but it's down the list of things that are in a head.
As other's have stated, What's the budget-actual availability, your expectations for target HP/TQ and @ what RPM, the true RPM range and usage both min. average and max RPM. sounds like you have a nice weather hot rod.
I mostly agree with Lowend's post #16 above (DCR info-no) but would look at the E-Tec 170 if aluminum, or the L31's staying Iron. I spent the day on the dyno yesterday (Vortec headed 350) and my buddy just got a nice set of Vortec's in while there, I was looking at them, maybe he will sell them all done up and ready to go, I'll find out if you like.
He builds engines for some Maritime customers and I have built the carbs for them, they are very happy, the workmanship is guaranteed and we are in Eastern Ontario.
I look at it this way, pick the the 200cc runner head with 255 cfm @ .500, you will be peaking around 6,300 with your 355, factor in 8% overrun to take advantage of the complete curve and your in the 6,800 range, so, next question is now Hyd or solid cam, open plenum or dual plane, gearing, weight, shift recover rpm. and bottom end TQ average loss with the larger runner head.
The L31 is 170cc, 235cfm and will peak around 5,800, add in 8% and your at 6,300, so your good with hyd. FT or roller, your budget will be blown on the roller. And I target a 1,500 rpm peak spread with a carb, so your at the 4,300 rpm or even less with a dual plane, car will be quicker, easier to tune and will get better MPG's, JMO.
Thanks everyone for the replies and information.
I would like something around 350 hp at least and maybe around 380 to 400 tq would be great. I still get leaning towards L31 vortecs with them upgraded to handle a high lift cam shaft.
What's the opinion on reach approximately 350 hp and 380 tq with using vortec heads?
Let's just say I do find a set of vortec heads and when I go look at them what are things I should look for besides the two usable casting numbers.?
Would 190,000 km or 118,000 miles be considered a lot of mileage on a set of vortec heads?
I would consider buying a set of heads out of province as well. I'm not sure what the price may be though to rebuild and ship them here to Nova Scotia. Thanks
RE: which heads, this has more information than you could imagine
RE: 350 Horsepower - with L31 heads on a 350, you could throw the engine down the stairs and make 350 HP. Combine those heads, with a cam [email protected] and you'll get (beyond) there easily.
RE: Summit brand heads, I tend to stay away from Summit branded items in general. Summit doesn't manufacture anything. All of these products are a white-box of someone else. Sometimes those white-box items are factory 2nds, sometimes they're just a bulk run. Which is it, you'll never know. For something complex like cylinder heads, I'm not taking that risk.